This is a classic 2 transistor astable multivibrator. Many other NPN small signal or switching transistors can be used, including 2N4401, PN2222 or 2N2222 using the circuit on the left. The circuit can also be inverted using PNP transistors such as 2N3906,....

It`s a typical AMV (Astable MultiVibrator) setup. The capacitor gets charged through both resistors until 2/3 Vcc is reached (internal comparator level). This sets a flip-flop which activates the Discharge output (DIS). Through DIS and the potentiometer, the....

Here is the circuit diagram of a fuse that has an automatic status indicator. This circuit can be added to circuit that operates from 12V DC. As long as the fuse is intact, the LED D3 will glow continuously and when the fuse blows off the LED will start and....

An astable multivibrator, often called a free-running multivibrator, is a rectan ­gular-wave generating cir ­cuit. Unlike the monostable multivibrator, this circuit does not require any ex ­ternal trigger to change the state of the output, hence the name....

It`s state is constantly changing and this change affect the flow of current and voltage and the effect will be visible with the two leds. The speed of the led flasher may be adjusted with potentiometer P1. Being an astable multivibrator, the circuit has no....

This is the circuit diagram of lamp flasher operated from mains. By this you can flash up to 200 Watt lamps at rates determined by you. IC NE555 is wired as an astable multivibrator for producing the pulses for flashing the lamp. The flashing rate can be set....

This circuit utilising a 555 timer IC can be used as an alarm system to prevent the theft of your luggage, burglars breaking into your house etc. The alarms goes ON when a thin wire, usually as thin as a hair is broken. The circuit is straightforward. It....

A lot of electronic circuits using NE555 timer IC Here is the circuit diagram of a police siren based on NE55 timer IC. The circuit uses two NE555 timers ICs and every of them are wired as astable multivibrators. The circuit will be powered from something....

This light dimmer is used to dim the intensity of 12V light bulbs using the well-known 555 timer that is configured as an astable multivibrator. The pulses....

It doesn`t break if being little even if it crosses the value of the input/output electric current characteristic. It breaks when short-circuiting and doing the extreme thing in the output. It is explained by the following circuit operation but because the....

A circuit that can be used to flash two Christmas stars alternatively is given here. The IC1 NE 555 is wired as an astable multivibrator here. When there is a positive pulse from the output of IC1, the transistor Q1 conducts and the relay K1 gets activated.....

Blinks 2 LEDs timely in sequence. Will somebody explain its working I know that capacitor will charge and during the charging the LED will off and whenthey discharge they will on the LED. But why transistor are there..

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Transistorised Astable Multivibrator is a cross coupled transistor network capable of producing sharp continuous square wave. It is free running oscillator or simply a regenerative switching circuit using positive feedback. Astable Multivibrator switches....

The two parts` component parameters and models of the circuit are corresponding to simultaneously obtain a rectangular wave with duty ratio of 1:1, its frequency f = 0.7/RB ¢ C. RB is Rb1 or Rb2 in the figure, and its upper limit value Rb1 < 0.5?RC1 ; Rb2 <....

The 555 on the right is wired as an alarm sound generator and the second 555 timer on the left is a 1 Hz astable multivibrator. The output of the left timer is to modulate the frequency of the right timer. This process will cause the right timers frequency....

This circuit included in the category astable multivibrator. This circuit is used to test? N-Mosfets (the power kind e.g irf830), whether it works or not. If...

This is basically a flasher circuit modified to turn on and off a bulb instead of a LED. It uses a 555 timer IC working as an astable multivibrator. The flashing rate can be varied from very fast to a maximum of once in 1. 5 sec by varying the preset VR1. ..

This easy electronic buzzer circuit built based on timer works for gaining the frequency. The IC timer NE 555 used as astable multivibrator operating at about 1kHz and produces a sound when switched on. The sound frequency can be adjusted b....

Its a simple fly back tester, I believe you can built it, i use this circuit to test all of high freq transformer like SMPS transformer or fly back, this circuit is an astable multivibrator with about 90Khz freq, 12 vdc as vcc. To check SMPS transformer or....

This circuit produces a sound similar to the police siren. It makes use of two 555 timer ICs used as astable multivibrators. The frequency is controlled by the pin 5 of the IC. The first IC (left) is wired to work around 1Hz. The 47uF capacitor is charged....

This converter 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....

Here is a 100 Watt inverter circuit using minimum number of components. Here we use CD 4047 IC from Texas Instruments for generating the 100 Hz pulses and four 2N3055 transistors for driving the load. The IC1 Cd4047 wired as an astable multivibrator produces....

In this circuit a standard op-amp is wired as an astable multivibrator. The output is non-symmetrical but has the advantage that the timing is controlled by only 1 resistor and capacitor, in this case, the 100k variable resistor, U2 and 100u capacitor C1.....

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This device was designed on request and allows sequential operation of four Leds either to left or right direction, obtained by means of a 7555 CMos timer IC (IC1) wired as an astable multivibrator driving a Decade counter (IC2). This IC is set to count a....

This is a very basic circuit for flashing one or more LEDS and also to alternately flash one or more LEDs. It uses a 555 timer setup as an astable multivibrator with a variable frequency. With the preset at its max. the flashing rate of the LED is about 1/2....

A monostable multivibrator using IC CD4538. It is a precision monostable/astable multivibrator IC free from false triggering. This can be used for various application in which precise timing cycle is required. CD4538 is the precision monostable/astable....

Astable multivibrator or oscillator circuit is based on positive feedback. We can design such circuit using op-amp, logic gates, or transistors. Here we can...

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This is the circuit diagram of a ding dong sound generator based on two NE555 timer ICs. The circuit is designed to toggle between two adjustable frequencies to produce the ding dong sound. The first NE555 (IC1) is wires as an astable multivibrator operating....

Astable Multivibrator can be designed by using 555 timer IC, Op Amps and also using transistors. The 555 IC provide accurate time delay from mille seconds to hours. The frequency of oscillation can be controlled manually by simple modification. This is a....