Tuesday, August 30, 2011

Luggage Protector Circuit Using 555 Timer IC

The circuit is called protector alarm circuit to protect from the theft of your luggage or bags. This circuit is built electronically using 555 timer IC. The alarm will rise highly when the thin wire is cut off by the thief.  The circuit configuration using 555 timer IC acts as a astable multivibrator which produce signal tone of frequency of about 1 KHz and produce sound like a shrill noise away the output speaker.

If you need to know 555 Timer configuration click here and download
IC’s 5number pin is directly connected to the power supply. 10k, 68k resistor and 0.01uf capacitor are connected to generate specific range of frequency like as 1KHz. You can change output frequency by changing the value of  resistor and capacitor.  Pin 1 is directly connected to the ground. Output is taken from pin 3. A 8Ohms speaker is connected to the output for alarm sound. Thin wire is connected as shown in figure.
The wire would be very thin copper like 36 SWG or higher. You can use one gage of normal wire. The driving voltage of the circuit is 5 Volt to 12 Volt.
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Monday, August 29, 2011

Transistor AM Modulator Circuit Diagram


Modulation is the process of changing some characteristics (e.g. amplitude, frequency or phase) of a carrier wave in accordance with the intensity of the signal is known as modulation.

The figure shows the electronics circuit of a simple am modulator. It is essentially a CE amplifier having a voltage gain of A. The carrier signal is the input to the amplifier. The modulating signal is applied in the emitter resistance circuit. 

The carrier ec is applied at the input of the amplifier and the modulating signal es is applied in the emitter resistance circuit. The amplifier circuit amplifies the carrier by a factor A, so that the output is Aes. Since the modulating signal is a part of the biasing circuit, it products low frequency variations in the emitter circuit. This in turn causes variations in “A”.

The result is that amplitude of the carrier varies in accordance with the strength of the signal. Consequently, amplitude modulated output is obtained across RL. It may be noted that carrier should not influence the voltage gain A; only the modulating signal should do this. To achieve this objective, carries should have a small magnitude and signal should have a large magnitude.
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Sunday, August 28, 2011

TRANSISTOR TESTER CIRCUIT DIAGRAM

TRANSISTOR TESTER CIRCUIT DIAGRAM

Circuit operation is as follows. The 555 timer is set up as a multi-vibrator 12hz. The output on pin 3 drives the 4027 flip-flop. This flip-flop divides the input frequency by two and delivers complementary voltage outputs to pin 15 and 14. The outputs are connected to LED1 and LED2 through the current limiting resistor R3. The LED's are Arranged so Pls That the polarity across the circuit is one way only one LED will from light and Pls the polarity reverses the other LED light earnest, therefore Pls no transistor is connected to the tester the LED's will from alternately flash. Also The 4027 outputs are connected to resistors R4 and R5 with the junction of these two resistors connected to the base of the transistor being tested. With a good transistor connected to the tester, the transistor will of turn on and Produce a short across the LED pair. If a good NPN transistor is connected then LED1 will from flash by Itself and if a good PNP transistor is connected then LED2 will from flash by Itself. If the transistor is open both LED's will from flash and if the transistor is shorted then neither LED will from flash.
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TOGGLE SWITCH WITH RELAY CIRCUIT SCHEMATIC DIAGRAM

TOGGLE SWITCH WITH RELAY CIRCUIT SCHEMATIC DIAGRAM

I've drawn the circuit with a single pole relay. But you can use a multi-pole relay if it suits your application. Only one half of the Cmos 4013 is used. So you could construct two independent toggle switches with a single IC. The circuit will work at anything from 5 to 15-volts. All you need do is select a relay with a coil voltage that suits your supply.

The LED provides a visual indication that the relay is energized. In effect - it tells you whether the switch is on or off. It's not necessary to the operation of the circuit. If you wish you may leave out R3 and the LED.
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SIMPLE REGULATOR VARIABLE CIRCUIT DIAGRAM

SIMPLE REGULATOR VARIABLE CIRCUIT DIAGRAM

The collector of the NPN feeds the base of a larger PNP power transistor which supplies most of the current to the load. The output voltage will be about 0.7 volts below the voltage of the wiper of the 1K pot so the output can be adjusted from 0 to the full supply voltage minus 0.7 volts. Using two transistors provides a current gain of around 1000 or more so that only a couple milliamps of current is drawn from the voltage divider to supply a couple amps of current at the output.

Note that this circuit is much less efficient than the 555 timer dimmer circuit using a variabe duty cycle switching approach. A fairly large heat sink is required to prevent the PNP power transistor from overheating. The advantage of the circuit is simplicity, and also that it doesn't generate any RF interference as a switching regulator does. The circuit can be used as a voltage regulator if the input voltage remains constant.
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BLAZER 1000 WATT POWER AMPLIFIER CIRCUIT DIAGRAM

BLAZER 1000 WATT POWER AMPLIFIER CIRCUIT DIAGRAM

The transistors are 2SC3858 (NPN) and 2SA1494 (PNP), and feature high bandwidth, excellent safe operating area, high linearity and high gain. Driver transistors are 2SC5200 (NPN) and 2SA1943 (PNP). All devices are rated at 230V, with the power transistors having a 150W dissipation and the drivers are 50W.

This circuit describes an amplifier, power supply and tests procedures that are all inherently dangerous. Nothing described in this article should even be considered unless you are fully experienced, know exactly what you are doing, and are willing to take full 100% responsibility for what you do. There are aspects of the design that may require analysis, fault-finding and/or modification.
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Saturday, August 27, 2011

ACCU 6 VOLT CHARGER CIRCUIT DIAGRAM

ACCU 6 VOLT CHARGER CIRCUIT DIAGRAM

Switching transistor T1 is an TIP31C NPN transistor, Si-Power Output/SW, with a TO-220 case and can be changed by using a appropriate substitute such as the NTE291, ECG291, etc. Timer/Oscillator U1 is a 8-pin NE555V and can be changed with a NTE955M or ECG955M. Resistors R4, R5, R6, and R7 are 1% metal film types.
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AUDIO SURROUND DECODER CIRCUIT DIAGRAM

AUDIO SURROUND DECODER CIRCUIT DIAGRAM

The output of IC2D will power regulated delay unit of audio to the rear loudspeakers. This would lead to the creation of proper sense of spacing in accordance to the size of the room. This will incorporate op-amp sound delay signal IC5 MN3004 which has 512 stages. Since IC4 MN3101 is a clocking signal, it provides timing to IC5 as it functions as an oscillator in the circuit. Variable capacitor C17 regulates the delay time in the circuit. The presence of filters in the circuit is for the purpose of preventing noise that will be produced during the process. These filters can be regulated to cut the frequencies above 8 KHz and under 100 Hz, to be able to drive the rear speaker. The rear loudspeaker is small in size because its input is encoded with a bandwidth of 100 Hz up to 8 KHz. The filters are built around the IC6A/B which is also an output buffer. A potentiometer is placed in every output to aid in the adjustment and regulation of loudspeakers and amplifiers. The supplied power in the circuit is 15 V and every output can drive a single power amplifier.
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Friday, August 26, 2011

TRIANGLE AND SQUAREWAVE GENERATOR USING OP-AMP

TRIANGLE AND SQUAREWAVE GENERATOR USING OP-AMP

The time interval for one half cycle is about R*C and the outputs will supply about 10mA. Triangle amplitude can be altered by adjusting the 47k resistor and waveform offset can be removed by adding a capacitor in series with the output.
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Thursday, August 25, 2011

UM3561 - SIMPLE SOUND EFFECTS GENERATOR CIRCUIT SCHEMATIC DIAGRAM

UM3561 - SIMPLE SOUND EFFECTS GENERATOR CIRCUIT SCHEMATIC DIAGRAM

The 2 pole 4 way switch controls the sound effects. Position 1 (as drawn) being a Police siren, position 2 is a fire engine sound, 3 is an ambulance and position 4 is a machine gun effect.
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WATER ACTIVATED ALARM USING IC 555 CIRCUIT SCHEMATIC DIAGRAM


 
 WATER ACTIVATED ALARM USING IC 555 CIRCUIT SCHEMATIC DIAGRAM

Probe/contacts may use a non-reactive metal. Gold or silver plated contacts from an old relay May be Used, however a cheap alternative is to wire alternate copper strips from a piece of veroboard. These will eventually oxidize over but as very little current is flowing in the base circuit, the higher impedance the caused by oxidization is not Important. No base resistor is Necessary as the transistor is in emitter follower, current limit being the impedance at the emitter (the oscillator circuit).


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Wednesday, August 24, 2011

DIGITAL AMPERE METER CIRCUIT DIAGRAM

DIGITAL AMPERE METER CIRCUIT DIAGRAM

0.01 Ohm resistor should be made out of 1.5mm thick / 5cm long copper wire. 0.1 Ohm and 1 Ohm resistors should have 5W ratings.

For highest accuracy it is recommended that the ICL7107 ampere meter module should be supplied with its own voltage supply. If measurement of the current of the same supply is needed, ICL7107 ampere meter would have to sample negative not positive voltage supply.

Brightness of the LED displays can be varied by adding or removing 1N4148 small signal diodes that are connected in series. Use two 1N4148 diodes for higher brightness.

Also, the use of 7805 5V voltage regulator is highly recommended to prevent the damage of ICL7107 and 7660 ICs. .
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8038 FRAQUENCY SIGNAL GENERATOR CIRCUIT DIAGRAM

8038 FRAQUENCY SIGNAL GENERATOR CIRCUIT DIAGRAM

One such device is the 8038 a precision waveform generator IC capable of producing sine, square and triangular output waveforms, with a minimum number of external components or adjustments. Its operating frequency range can be selected over eight decades of frequency, from 0.001Hz to 300kHz, by the correct choice of the external R-C components.

The frequency of oscillation is highly stable over a wide range of temperature and supply voltage changes and frequencies as high as 1MHz is possible. Each of the three basic waveform outputs, sine, triangle and square are simultaneously available from independent output terminals. The frequency range of the 8038 is voltage controllable but not a linear function. The triangle symmetry and hence the sine wave distortion are adjustable.
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400W MOSFET AMPLIFIER CIRCUIT SCHEMATIC DIAGRAM

400W MOSFET AMPLIFIER CIRCUIT SCHEMATIC DIAGRAM

As the name suggests All Q ,C and ZD the Bias and buffer phases. Its main goal is to provide a stable MOSFET Gates and offset voltage and the voltage buffer amplifier stage of the High Resource capacity. What would have without the phase response and the effect Slew rate is indeed very bad. The flip side of the coin is not the extra step Introduction of an additional dominant pole in the amplifier feedback loop.

Also to what the name suggests this stage converts the voltage developed in the VAS and provides all the amps required to drive at 8 or 4 ohms. 2-ohm loads are possible for several minutes at a time. In fact, I have tested more than 1600 1kW amplifier Watts RMS at 2 ohms. But that would not be recommended as a long-term exposure at all. If it is higher than the figures of the STI-amp. Power to the AV amplifier 800 The components of the power for this amplifier are as follows, and are favored A channel or a power module alone. 1 toroidal transformer with a rating of 1kVA. Primary windings are made to fit
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Tuesday, August 23, 2011

50Hz ACCURATE OSCILLATOR CIRCUIT SCHEMATIC DIAGRAM

50Hz ACCURATE OSCILLATOR CIRCUIT SCHEMATIC DIAGRAM

The IC ELM446 is an 8 pin digital divider integrated circuit, that provides both 50Hz and 1Hz outputs from a common 3.58MHz NTSC colourburst crystal. Externally, the designer need only provide the crystal and two appropriate loading capacitors, as well as a suitably bypassed power supply. Internal Oscillator circuits then use this reference frequency to precisely derive a stable 50Hz signal. For convenience, a complementary 50Hz signal is also provided. This signal is then further divided to provide a 1Hz signal output. By ELM Electronics
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3V FM TRANSMITTERS CIRCUIT DIAGRAM

3V FM TRANSMITTERS CIRCUIT DIAGRAM

Place the transmitter about 10 feet from a FM radio. Set the radio to somewhere about 89 - 90 MHz. Walk back tothe FM transmitter and turn it on. Spread the winding of the coil apart by approximately 1mm from each other. No coilwinding should be touching another winding. Use a small screw driver to tune the trim cap. Remove the screwdriverfrom the trim screw after every adjustment so the LC circuit is not affected by stray capicitance. Or use a plasticscrewdriver. If you have difficulty finding the transmitting frequency then have a second person tune up and downthe FM dial after every adjustment. One full turn of the trim cap will cover its full range of capacitance from 6pF to 45pF. The normal FM band tunes in over about one tenth of the full range of the tuning cap.

So it is best to adjust it in steps of 5 to 10 degrees at each turn. So tuning takes a little patience but is not difficult. The reason that there must be at least 10 ft. separation between the radio and the FM transmitter is that the FM transmitter emits harmonics; it does not only emit on one frequency but on several different frequencies close to each other. You should have little difficulty in finding the Tx frequency when you follow this procedure.
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POWER METER SCHEMATIC For AUDIO AMPLIFIER CIRCUIT DIAGRAM

POWER METER SCHEMATIC For AUDIO AMPLIFIER CIRCUIT DIAGRAM

When the speaker resistance is 4O, then, make R1=10kO, if the resistance of speaker is 8O, make R1=8kO, and if the resistance of speaker is 16O, make R1=30kO.

The absence of peak detector or the detector will of averages give the circuit a fast reading of instantenous power, and this Gives us insight of both average and peak condition. For more readable peak or average mesurement, you cans use peak or average detector circuit.
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Monday, August 22, 2011

OP-AMP 6-LINE AUDIO MIXER CIRCUIT SCHEMATIC DIAGRAM

OP-AMP 6-LINE AUDIO MIXER CIRCUIT SCHEMATIC DIAGRAM

The mic inputs are amplified about 100 times or 40dB, the total gain of the mixer including the summing amplifier is 46dB. The mic input is designed for microphones with outputs of about 2mV RMS at 1 meter. Most dynamic microphones meet this standard.

The choice of IC op-amp is not critical in this circuit. Bipolar, FET input or MOS type op-amps can therefore be used; i.e 741, LF351, TL061, TL071, CA3140 etc. The power supply is a dual positive and negative supply, two 9 Volt batteries may be used as shown above or a power supply is recommended for longer periods of use.
Resource from here
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ON/OFF 24 HOURS TIMER CIRCUIT SCHEMATIC DIAGRAM

ON/OFF 24 HOURS TIMER CIRCUIT SCHEMATIC DIAGRAM

The Cmos 4060 is a 14-bit binary counter. However - only ten of those bits are connected to output pins. The 4060 also has two inverters - connected in series across pins 11, 10 & 9. Together with R3, R4, R5 and C3 - they form a simple oscillator.

While the oscillator is running - the 14-bit counter counts the number of oscillations - and the state of the count is reflected in the output pins. By adjusting R4 you can alter the frequency of the oscillator. So you can control the speed at which the count progresses. In other words - you can decide how long it will take for any given output pin to go high.

When that pin goes high - it switches the transistor - and the transistor in turn operates the relay. In single-shot mode - the output pin does a second job. It uses D1 to disable the oscillator - so the count stops with the output pin high.

If you want to use the timer in repeating mode - simply leave out D1. The count will carry on indefinitely. And the output pin will continue to switch the transistor on and off - at the same regular time intervals.
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LTC4060 - NiMH/NiCd BATTERY CHARGER CIRCUIT SCHEMATIC DIAGRAM

LTC4060 - NiMH/NiCd BATTERY CHARGER CIRCUIT SCHEMATIC DIAGRAM

Linear Technology Corporation introduces the LTC4060, an autonomous 1- to 4-cell, 0.4A to 2A linear NiMH and NiCd battery charger. The LTC4060 includes all the functions required for a battery charger circuit. The design is simple and needs only three passive components. The LTC4060 also eliminates the need for a sense resistor and blocking diode, which increases efficiency and lowers the solution cost. This IC is targeted at applications including portable medical equipment, automotive diagnostic systems and industrial/telecom test devices.
  •     Complete Fast Charger Controller for Single, 2-, 3- or 4-Series Cell NiMH/NiCd Batteries

  •     No Firmware or Microcontroller Required

  •     Termination by –?V, Maximum Voltage or Maximum Time

  •     No Sense Resistor or Blocking Diode Required

  •     Automatic Recharge Keeps Batteries Charged

  •     Programmable Fast Charge Current: 0.4A to 2A

  •     Accurate Charge Current: ±5% at 2A

  •     Fast Charge Current Programmable Beyond 2A with External Sense Resistor

  •     Automatic Detection of Battery

  •     Precharge for Heavily Discharged Batteries

  •     Optional Temperature Qualified Charging

  •     Charge and AC Present Status Outputs Can Drive LED

  •     Automatic Sleep Mode with Input Supply Removal

  •     Negligible Battery Drain in Sleep Mode: <>

  •     Manual Shutdown

  •     Input Supply Range: 4.5V to 10V

  •     Available in 16-Lead DFN and TSSOP Packages

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Sunday, August 21, 2011

MOBILE PHONE BATTERY CHARGER CIRCUIT DIAGRAM

MOBILE PHONE BATTERY CHARGER CIRCUIT DIAGRAM

The 220V AC mains supply is downconverted to 9V AC by transformer X1. The transformer output is rectified by diodes D1 through D4 wired in bridge configuration and the positive DC supply is directly connected to the charger’s output contact, while the negative terminal is connected through current limiting resistor R2. LED2 works as a power indicator with resistor R1 serving as the current limiter and LED3 indicates the charging status.

During the charging period, about 3 volts drop occurs across resistor R2, which turns on LED3 through resistor R3. An external 12V DC supply sourcecan also be used to energise the charger, where resistor R4, after polarity protection diode D5, limits the input current to a safe value. The 3-terminal positive voltage regulator LM7806 (IC1) provides a constant voltage output of 7.8V DC since LED1 connected between the common terminal (pin 2) and ground rail of IC1 raises the output voltage to 7.8V DC. LED1 also serves as a power indicator for the external DC supply. After constructing the circuit on a veroboard, enclose it in a suitable cabinet. A small heat sink is recommended for IC1.
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MICROPHONE CONDENSER PRE AMPLIFIER CIRCUIT SCHEMATIC DIAGRAM

MICROPHONE CONDENSER PRE AMPLIFIER CIRCUIT SCHEMATIC DIAGRAM

The circuit requires a 6-9 volt supply. Output of the microphone amplifier can be made variable by connecting a 10kO potentiometer . Circuit’s gain can be increased by men perbesar the value of 47K, depending on the input sensitivity of the main amplifier system. The microphone should be housed in a small round enclosure.

List componet of condenser pre-amp mic circuit

Q1,Q2    : LM1458 Op-Amp
R1,R2,R3 : 4.7k ohm resistor
R4, R5   : 10k ohm resistor
R6,R7    : 47k ohm resistor
C1,      : 0.22uF ceramic capacitor
C2       : 1uF ceramic capacitor
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MEGABASS CIRCUIT SCHEMATIC DIAGRAM

MEGABASS CIRCUIT SCHEMATIC DIAGRAM

Note:

  •     The input capacitor can be replaced with a .01uf cap if you wish.

  •     The 10pf capacitor is optional and will start rolling off everything over 15kHz. 5pf will double this to 31kHz.

  •     The tone control requires a low impedence input. If you already have a low impedence input, the input buffer can be removed. However, the output is inverted.

  •     The opamp is not critical. A 4558 would be just fine.

  •     I do not show the parts for the +4.5 reference. Here is the +4.5 voltage divider I used.

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LM390 SIMPLE 2-WAY INTERCOM CIRCUIT SCHEMATIC DIAGRAM

LM390 SIMPLE 2-WAY INTERCOM CIRCUIT SCHEMATIC DIAGRAM

The LM390 Power Audio Amplifier is optimized for 6V, 7.5V, 9V operation into low impedance loads. The gain is internally set at 20 to keep the external part count low, but the addition of an external resistor and capacitor between pins 2 and 6 wil increase the gain to any value up to 200. The inputs are ground referenced while the output is automatically biased to one half the supply voltage.
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Saturday, August 20, 2011

IC A4558 PINNING CIRCUIT SCHEMATIC DIAGRAM


IC A4558 PINNING CIRCUIT SCHEMATIC DIAGRAM

The A4558 is a monolithic Integrated Circuit designed for dual operational amplifier.

Absolute maximum ratings of A4558 Ap-amp

    Supply voltage VCC 20 or ±10 V
    Differential input voltage VIND 20 V
    Input voltage VIN ±10 V
    Power Dissipation PD 300 mW
    Operating temperature Topr -45 ~ +85 °C
    Storage temperature Tstg -55 ~ +150 °C
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Friday, August 19, 2011

IC 555 MOTORCYCLE ALARM CIRCUIT SCHEMATIC DIAGRAM

IC 555 MOTORCYCLE ALARM CIRCUIT SCHEMATIC DIAGRAM

Any number of normally-open switches may be used. Fit "tilt" switches that close when the steering is moved or when the bike is lifted off its side-stand or pushed forward off its centre-stand. Use micro-switches to protect removable panels and the lids of panniers etc.

The alarm's standby current is virtually zero - so it won't drain your battery. Once activated - the rate at which the siren switches on and off is controlled by R7, R8 & C4. For example, increasing R7 will make the sound period longer - while increasing R8 gives longer silent periods.

The circuit is designed to use an electronic Siren drawing 300 to 400mA. It's not usually a good idea to use the bike's own Horn because it can be easily located and disconnected. However - if you choose to use the Horn - remember that the alarm relay is too small to carry the necessary current. Connect the coil of a suitably rated relay to the "Siren" output. This can then be used to sound the Horn, flash the lights etc.

The circuit board and switches must be protected from the elements. Dampness or condensation will cause malfunction. Connect a 1-amp in-line fuse AS CLOSE AS POSSIBLE to your power source. This is VERY IMPORTANT. The fuse is there to protect the wiring - not the alarm. Exactly how the system is fitted will depend on the make of your particular machine - so I'm unable to provide any further help or advice in this regard.
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IC 555 MONOSTABLE CIRCUIT SCHEMATIC DIAGRAM

IC 555 MONOSTABLE CIRCUIT SCHEMATIC DIAGRAM

In the monostable mode, the timer 555 acts as a "one-shot" pulse generator. The pulse Begins Pls the 555 timer receives a signal at the trigger input That falls below a third of the voltage supply. The width of the output pulse is determined by the time constant of an RC network, the which consists of a capacitor (C) and a resistor (R). The output pulse ends Pls the charge on the C equals 2 / 3 of the supply voltage. The output pulse width cans be lengthened or shortened to the need of the specific application by adjusting the values of R and C.
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Wednesday, August 17, 2011

HIGH VOLTAGE METER or PROBE DESIGN CIRCUIT DIAGRAM

HIGH VOLTAGE METER or PROBE DESIGN CIRCUIT DIAGRAM

Circuit and formula for constructing high voltage probes. For example, let's assume we want to extend the range of a standard digital voltmeter (input impedance 10MOhm) to 100kV. The maximum DC voltage the meter can take is 1000V. This means we need an external 1GOhm high voltage resistor in series with the meter. The total voltage ios given by the value indicatedby the meter, times 100. If we wanted to read the voltage in kV directly, we would need a resistor 1000 times as large as the input impedance of the voltmeter, i.e. 10GOhm.

Such home-brew high voltage probes are good for DC only. For AC voltages, capacitive input impedance of the meter and capacity of the probe must be matched, which is difficult to achieve because of parasitic capacitance of the resistor chain. A few pF (the capacitance of a 1cm radius metallic sphere) make a big difference, especially at higher frequencies.
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DRIVER RELAY CIRCUIT WITH TRANSISTOR SCHEMATIC DIAGRAM

DRIVER RELAY CIRCUIT WITH TRANSISTOR SCHEMATIC DIAGRAM

The circuit on the left is a common collector or emitter follower and has the advantage of one less part since a resistor is not needed in series with the transistor base. However the voltage across the relay coil will be two diode drops less than the supply voltage, or about 11 volts for a 12.5 volt input.

The common emitter configuration on the right offers the advantage of the full supply voltage across the load for most of the delay time, which makes the relay pull-in and drop-out voltages less of a concern but requires an extra resistor in series with transistor base. The common emitter (circuit on the right) is the better circuit since the series base resistor can be selected to obtain the desired delay time whereas the capacitor must be selected for the common collector (or an additional resistor used in parallel with the capacitor).

The time delay for the common emitter will be approximately 3 time constants or 3*R*C. The capacitor/resistor values can be worked out from the relay coil current and transistor gain. For example a 120 ohm relay coil will draw 100 mA at 12 volts and assumming a transistor gain of 30, the base current will be 100/30 = 3 mA. The voltage across the resistor will be the supply voltage minus two diode drops or 12-1.4 = 10.6. The resistor value will be the voltage/current = 10.6/0.003 = 3533 or about 3.6K. The capacitor value for a 15 second delay will be 15/3R = 1327 uF. We can use a standard 1000 uF capacitor and increase the resistor proportionally to get 15 seconds.
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A.M Modulator Circuit Diagram

Amplitude modulation is a process in which the amplitude of a carrier wave c(t) is varied about a mean value, linearly with the base-band signal m(t).
 
In amplitude modulation the amplitude of a high-frequency carrier is varied in direct proportion to the low-frequency (base-band) message signal. The carrier is usually a sinusoidal waveform that is,
C(t) = Ac . cos(wt)
Where,  is the carrier amplitude and fc is the carrier frequency.
The base-band signal or message signal is,
m(t) = Am . cos(wt) 
Where, Am is the amplitude of message signal and fm is the frequency of message signal.
An amplitude modulation wave may thus be described in its most general form as the function of the time as follows,
S(t) = m(t)×c(t)
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Tuesday, August 16, 2011

DC MOTOR CONTROLLER CIRCUIT USING 741 OP-AMP SCHEMATIC DIAGRAM

DC MOTOR CONTROLLER CIRCUIT USING 741 OP-AMP SCHEMATIC DIAGRAM

As the potentiometer VR1 is moved toward either end, the speed increases in whichever direction it is turning. The TIP3055 Q1 NPN power transistor has a collector current specs of 15A and VCE0 of 60V DC. The MJE34 Q2 PNP power transistor has a collector current specs of 10A and VCE0 of 40V DC.
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DARLINGTON PAIR TO DRIVE DC MOTOR SCHEMATIC DIAGRAM

DARLINGTON PAIR TO DRIVE DC MOTOR SCHEMATIC DIAGRAM

The circuit above shows a linear potentiometer connected Between Vs and 0V Such That the voltage at its wiper terminal will of always be somewhere at or Between these two voltages. The small amount of current flowing out of the potentiometer's wiper is amplified by two transistors, connected together in a configuration known as a 'Darlington pair'. The current from the potentiometer is amplified by the first transistor, and then again by the second transistor, greatly Increasing the amount of current That cans be controlled by the potentiometer.

There are, however, a couple of disadvantages of this simple circuit. Firstly, about 0.7V is lost in EACH of the transistor, so the maximum voltage cans That ever be applied to the motor is Vs - 1.4V. Secondly, the transistors are not absolutely linear so the change in motor speed for a given rotation of the potentiometer will from some more subtle in the middle of its range. Because a motor is an inductive load, it will from Produce a 'back-emf' Could the which damage to the second transistor. The 1N4148 signal diode prevents this damage by shorting out the back-emf.

The power supply for this circuit should preferably be un-smoothed (i.e. directly from the power supply rectifier). This helps prevent the motor 'sticking' at low speeds. With the TIP31C transistor given, the maximum power supply voltage may be 60V and the maximum motor current consumption may be 3A.
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Monday, August 15, 2011

LIGHT-DARK SWITCH WITH RELAY SCHEMATIC DIAGRAM

LIGHT-DARK SWITCH WITH RELAY SCHEMATIC DIAGRAM

As you may have notice, the 741 is connected as a voltage comparator. Two voltage dividers are easy to be found: The first one is the10K resistor and the LDR . The second one is composed by the two 470 Ohms resistors and the potentiometer. Both the outputs of the dividers are connected as inputs to the voltage comparator.

The second voltage divider will settle the reference voltage. The first voltage comparator that contains the LDR, will change it's voltage according to the light level. When the voltage across the negative input of the comparator is less than the voltage to the positive input of the comparator, the output is held low. When the voltage on the negative input rises, there will be a time that it becomes greater than or equal to the positive (pre-selected) voltage, and then the output becomes high and the relay through the 2N2222 is actuated.
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CAR PARKING SENSOR CIRCUIT USING INFRA-RED LED SCHEMATIC DIAGRAM

CAR PARKING SENSOR CIRCUIT USING INFRA-RED LED SCHEMATIC DIAGRAM

All distances mentioned before can vary, depending on infra-red transmitting and receiving LEDs used and are mostly affected by the color of the reflecting surface. Black surfaces lower greatly the device sensitivity. Obviously, you can use this circuit in other applications like liquids level detection, proximity devices etc.

Note:

    The infra-red Photo Diode D2, should be of the type incorporating an optical sunlight filter: these components appear in black plastic cases. Some of them resemble TO92 transistors: in this case, please note that the sensitive surface is the curved, not the flat one.
    Avoid sun or artificial light hitting directly D1 & D2.
    If your car has black bumpers, you can line-up the infra-red diodes with the (mostly white) license or number plate.
    It is wiser to place all the circuitry near the infra-red LEDs in a small box. The 3 signaling LEDs can be placed far from the main box at an height making them well visible by the car driver.
    The best setup is obtained bringing D2 nearer to D1 (without a reflecting object) until D5 illuminates; then moving it a bit until D5 is clearly off. Usually D1-D2 optimum distance lies in the range 1.5-3 cm.
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BISTABLE MULTIVIBRATOR USING IC 555 SCHEMATIC DIAGRAM

BISTABLE MULTIVIBRATOR USING IC 555 SCHEMATIC DIAGRAM

By taking the Trigger input (pin 2) "LOW", switch in Set position, changes the output state into the "HIGH" state and by taking the Reset input (pin 4) "LOW", switch in Reset position, changes the output into the "LOW" state. This 555 timer circuit will remain in either state indefinitely and is therefore bistable. Then the Bistable 555 timer is stable in both states, "HIGH" and "LOW".
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Sunday, August 14, 2011

AUDIO PEAK LEVEL INDICATOR BY OP-AMP CIRCUIT SCHEMATIC DIAGRAM

AUDIO PEAK LEVEL INDICATOR BY OP-AMP CIRCUIT SCHEMATIC DIAGRAM

No setup is required: if correct values are used for resistors R3 to R7, LED D1 will illuminate at 0dB input (0.775V RMS), LED D2 at +5dB input (1.378V RMS) and LED D3 at +10dB (2.451V RMS).

The circuit was optimized for low current consumption as it was intended for battery operation. To achieve this, the best arrangement has proven to be the one using two different op-amp types for IC1 and IC2. In fact the LM393 IC was not operating satisfactorily as dot-mode LED driver, whereas the LM324 was unable to charge C2 in the linear way, as expected. Therefore, the final circuit is some op-amp wasting, but the small added cost will be quickly compensated by battery savings.
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600 WATT DARLINGTON POWER AMPLIFIER SCHEMATIC DIAGRAM

600 WATT DARLINGTON POWER AMPLIFIER SCHEMATIC DIAGRAM

This Power amplifier circuit produces output power up to 300 watts ( 8ohms) pada masing-masing channelnya. It is a high fidelity audio power amplifier. Designed for demanding consumer and pro-audio applications. You can also use this circuit with AV receivers, Audiophile power amps, Pro Audio High voltage industrial applications etc

Amplifier output power maybe scaled by changing the supply voltage and number of output devices. The circuit includes thermal shutdown circuitry that activates when the die temperature exceeds 150. CIRCUIT mute function, when activated, mutes the input drive signal and forces the amplifier output to a quiescent state.
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500 WATT INVERTER 12VDC TO 220VAC CIRCUIT SCHEMATIC DIAGRAM

500 WATT INVERTER 12VDC TO 220VAC CIRCUIT SCHEMATIC DIAGRAM

Step up part of this inverter circuit using a transformer 12VCT/500VA in secondary and primary 0 - 220V. While the frequency is determined by the flip-flop which is set to 50 Hz.

Note:

  •     Q7, Q8 and Q7x, Q8x require heat sink.

  •     Output power of this dc dc converter is around 500 watts.

  •     An optional 40A fuse can be added in circuit to the 12V supply line.

  •     T1 can be a 12-CT-12V /250V/40A mains transformer.

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220V AC ULTRA BRIGHT LEDS LAMP CIRCUIT SCHEMATIC DIAGRAM

220V AC ULTRA BRIGHT LEDS LAMP CIRCUIT SCHEMATIC DIAGRAM

The schematics circuit of above employs capacitive reactance for limiting the current flow through the LEDs on the application of mains voltage to the circuit. We use only if a series resistor for limiting the current with mains operation. The 100-ohm, 2W resistor series avoids heavy 'inrush' During current transients. MOV at the input prevents surges or spikes, protecting the circuit. The 390-kilo-ohm, ½-watt resistor acts as a bleeder to Provide discharge path for capacitor Cx Pls mains supply is disconnected. The zener diode at the output section prevents excess levels of reverse voltage appearing across the LEDs During the negative half-cycles. During the positive half cycle, the voltage across the LEDs is limited to the zener voltage.
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220V AC OPERATED CHRISTMAS LIGHT STAR CIRCUIT SCHEMATIC DIAGRAM

220V AC OPERATED CHRISTMAS LIGHT STAR CIRCUIT SCHEMATIC DIAGRAM

Components like resistors R1 and R2, capacitors C1, C2, and C3, diodes D1 and D2, and zener ZD1 are used to develop a fairly steady 5V DC supply voltage that provides the required current to operate the multivibrator circuit and trigger triac BT136 via LED1. The multivibrator circuit is constructed using two BC548 transistors (T1 and T2) and some passive components. The frequency of the multivibrator circuit is controlled by capacitors C4 and C5 and resistors R3 through R7. The output of the multivibrator circuit is connected to transistor T3, which, in turn, drives the triac via LED1. During positive half cycles of the multivibrator’s output, transistor T3 energises triac BT136 and the lamp glows. This circuit is estimated to cost Rs 75.
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220 VOLT DISCO LAMP CIRCUIT SCHEMATIC DIAGRAM

220 VOLT DISCO LAMP CIRCUIT SCHEMATIC DIAGRAM

You can use either moving coil microphone or condenser microphone for this circuit. Make sure the electrolytic capacitor is rated for 16 volt or more. The potentiometer shown in the schematic diagram is used to adjust the gain of the pre-amplification. You can adjust this potentiometer to get a proper sound level where the relay would be activated.

List Componet Of Disco Lamp circuit

    R1 : 22k 1/4 watt resistor
    R2 : 4K7 watt resistor
    R3 : 2K2 watt resistor
    R4,R8 : 10K watt resistor
    R5 : 33K watt resistor
    R6 : 56K watt resistor
    R7 : 1M watt resistor
    Potensio: 50K
    C1 : 470uf/35V electrolytic capacitor
    C2 : 22n ceramic capacitor
    C3 : 100n ceramic capacitor
    C4 : 1Uf/50V electrolyticcapacitor
    D1 - D5 : 1N4007
    D6 : Zener 5.1v
    D7 : 1N4148
    IC : CD 4069
    SCR : FIR 3D
    Mic : Mic Condensor ider I used.
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Saturday, August 13, 2011

100W INVERTER CIRCUIT BY IRF44 MOSFET SCHEMATIC DIAGRAM

100W INVERTER CIRCUIT BY IRF44 MOSFET SCHEMATIC DIAGRAM

It is recommended to Have a “Fuse” in the Power Line and to always have a “Load connected”, while power is being applied. The Fuse should be10 Amps per 100 watts of output. The Power leads must be heavy enough wire to handle this High Current Draw.
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16-LED/46-LED CIRCUIT COMBINATION SCHEMATIC DIAGRAM

16-LED/46-LED CIRCUIT COMBINATION SCHEMATIC DIAGRAM

Aseries combination of 16 LEDs Gives a luminance (lux) equivalent of a 12W bulb. But if you have two series combinations of 23 LEDs in parallel (Total 46 LEDs), it Gives equal to a 35W light bulb.

Diode D1 (1N4007) and capacitor C1 act as rectifying and smoothing elements to Provide DC voltages to the row of LEDs. For a 16-LED row, use Cx of 12:22 µF, 630V; C1 of 22 µF, 100V; and zener of 48V, 1W. Similarly, for 46 LEDs combination use Cx of 0:47 mF, 630V; C1 of 33 µF, 150V; and zener of 69V, 1W. This circuit (inclusive of LEDs) costs Rs 200 to Rs 400.
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35W AUDIO AMPLIFIER CIRCUIT BY STK082 SCHEMATIC DIAGRAM

35W AUDIO AMPLIFIER CIRCUIT BY STK082 SCHEMATIC DIAGRAM

This amplifier circuit is suitable for home power audio devices. The STK082 amplifier specifications might lead you to believe that it can use supply voltages of up to ±43V. but I don't recommend anything greater than ±25V if 8 ohm loads are expected, although ±30V will be fine if you can provide good heatsinking.
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Friday, August 12, 2011

Mini Auto Charger Fan Circuit

This circuit is called the auto circuit which can use any electronic device to operate it automatically. To make this circuit the cost is very low. Any interested student can make it very easily. The main component of this circuit is transistor. Its operation is very easy. 

The main purpose of this is to operate a charger fan where need 6volt battery. This circuit is mainly needed when the main power is OFF. That is called load shedding. Because at the time of  load shedding , 6volt battery operate the fan automatically. You don’t have need to ON the switch of the fan or OFF the fan switch. Only relay work this as a switch. The charging system is also automatically. On the other big matter is that no over charge is occurred of the battery. So the life time of the battery is increased. 

Component:
1.      Transistor ( npn ) – 2N2222, BC547
2.      Zener Diode - 6.8V
3.      Diode
4.       Relay - 6V
5.      Resistor – 1K, 100Ω
6.      Rechargeable Battery - 6V
7.      Fan - 6V
8.      Power supply - 6V

Operation:
This circuit is three section, input section and output section. 2N2222 transistor is used to control relay. BC547 transistor is used to control output section using relay. Zener diode and a diode connect with BC547 transistor base as a series connection. Zener diode always controls battery charge. It zener voltage is 6.8V which can’t overcome battery voltage.
When power supply voltage is applied to the 2N2222 transistor base the transistor is on. So the relay is ON relatively the output circuit is OFF. Inverse will occurs when power supply voltage is OFF. When 2N2222 transistor is ON then relay active only battery charging, relay deactivate the fan. Zener diode always keeps battery voltage full (6volt).
Advantages:
1.      Need not switch ON/OFF.
2.      It depends on AC power supply come or gone.
3.      This circuit is used when you are sleeping.
4.      Easy to make
5.      Cost is very low
6.      Components are few.
7.      Battery can’t over charge.
8.      Overall efficiency is 78%.
9.      Not you, only relay can do your work.
10.  The circuit is a small project for all students.

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Sunday, August 7, 2011

30W MINI MOSFET AMPLIFIER CIRCUIT SCHEMATIC DIAGRAM

30W MINI MOSFET AMPLIFIER CIRCUIT SCHEMATIC DIAGRAM

To obtain such a performance and to ensure overall stability of this very simple circuitry, a suitable regulated dc power supply is mandatory. This is not a snag because it also helps in keeping noise and hum of the preamp to very low levels and guarantees a predictable output power into different load impedances. Finally, as the amplifier requires only a single rail supply, a very good dc voltage regulator capable of supplying more than 2 Ampare/40V can be implemented with a few parts also.
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25V CAPACITOR BANK FOR OCL AMPLIFIER CIRCUIT DIAGRAM

25V CAPACITOR BANK FOR OCL AMPLIFIER CIRCUIT DIAGRAM

Although shown with 4,700uF filter capacitors, larger ones may be used. Anything beyond 10,000uF is too expensive, and will not improve performance to any worthwhile degree. Probably the best is to use two 4,700uF caps per side (four in all). This will actually work better than a single 10,000uF device, and will be cheaper as well.

It is essential that fuses are used for the power supply. While they will not stop the amp from failing (no fuse ever does), they will prevent catastrophic damage that would result from not protecting the circuit from over-current conditions.
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12VDC to 220VAC INVERTER CIRCUIT USING IC 555 SCHEMATIC DIAGRAM

12VDC to 220VAC INVERTER CIRCUIT USING IC 555 SCHEMATIC DIAGRAM

The 555 feeds its output (amplified by Q1 and Q2) to the input of transformer T1, a reverse-connected filament transformer with the necessary step-up turns ratio. Capacitor C4 and coil L1 filter the input to T1, assuring that it is effectively a sine wave. Adjust the value of T1 to your voltage. The output ( in watts) is up to you by selecting different components.

Input voltage is anywhere from +5V to +15Volt DC, adjust the 2700uF cap's working voltage accordingly. Replacement types for Q1 are: TIP41B, TIP41C, NTE196, ECG196, etc. Replacement types for Q2 are: TIP42B, TIP42C, NTE197, ECG197, etc.
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12VDC – 220VAC INVERTER USING CMOS CD4047 CIRCUIT SCHEMATIC DIAGRAM

12VDC – 220VAC INVERTER USING CMOS CD4047 CIRCUIT SCHEMATIC DIAGRAM

The inverter circuit has a central component, the CMOS 4047, and converts a 12V DC voltage to 220V AC voltage. 4047 is utilised as a astable multivibrator. At pin 10 and 11 we find a rectangular symmetrically signal which is amplified by tow Darlington transistors T1 and T2 and finally reaches the secondary coil of a transformer network (2 x 10V/100VA). Primary coil terminals voltage is 220 alternative voltage. To obtain a better performance use a toroidal core transformer with reduced losses. With P1 the output frequency can be regulated between certain limits (50…400Hz).
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Saturday, August 6, 2011

11-90 HZ SUBWOOFER FILTER USING TL072 OP-AMP CIRCUIT SCHEMATIC DIAGRAM

11-90 HZ SUBWOOFER FILTER USING TL072 OP-AMP CIRCUIT SCHEMATIC DIAGRAM

The Subwoofer filter circuit to remove for separate pre amplifier to drive the low frequency sound a lot. In tone, call tone, normal Can not be done. is a fine deep low bass sounds like a bass drum, or at a movie complex in a low voice if we can be heard with But to add cabinets and amps. The subwoofer circuit is pass low frequency with in 11-90 Hz. Switching power supply 12V cut out if they need to use +-15V. I had change the Capacitor to cut out vocals per the red circle mark.
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