Schematic Diagrams

Useful schematic and wiring diagrams. ✔ ✔ Enjoy electronic circuits, let your idea comes to hardware


Discrete R/S Flip Flop

This circuit is an example of a set/reset flip flop. Set/reset flip flop is the simplest flip flop. This circuit using discrete components. Here is the schematic diagram : When this circuit obtain the power, only one of the transistors will conduct that causing the other components to remain off. This transistor can be turned […]

Astable and Monostable Multivibrators

Multivibrators is two state devices which is used extensively in digital electronics. The bistable multivibrators or called filp-flop are the basic memory devices used in sequential logic. Beside bistable multivibrator, there are also astable multivibrator which serves as an oscillator and the monostable multivibrator (on shot multivibrator) which can serve as a pulse source. The […]


Starting Network for Astable Multivibrator

A flip-flop that generates two unstable states (high-low) is called astable multivibrator, a fancy name for you to say it’s an oscillator. The very basic of such circuit consist of two transistor where the collector of each transistor is wired in such way they try to short the base of the other transistor through a […]


Opto-Coupled Discrete Pulse Stretcher

This is a pulse stretcher circuit using optocoupler. This circuit uses a 4N26 opto-coupler combined with a standard one-shot circuitry. This circuit is triggered by pulse about 3μs (minimum width)  at 15mA. The output’s amplitude of this circuit is not depend on the input’s amplitude. The output pulse amplitude is a function of (or proportional […]


555 IC LED Flasher for Up To 10 LEDs

This LED flasher circuit uses 555 IC, and is capable of driving up to 10 LEDs. The good news is, the use of multiple LEDs in series doesn’t increase the power consumption when compared with using only two LEDs. If we use only two LEDs, then we have to sink the power into a current […]

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Bi-Stable Multivibrator (RS Flip-FLop) with Op-Amp

This bi-stable circuit uses an op-amp, acts similar with RS flip-flop. Bi-stable circuit is a circuit with two stable states, low and remain low until set is triggered, or high and remain high until reset is triggered. Here is the schematic diagram of the circuit: Most Wanted Diagrams:bistable multivibrator using op ampbistable by using opampBISTABLE […]

One-Shot Multivibrator

A one shot multivibrator generate a fixed width pulse at the output when the input is triggered. This fixed width output should be consistent, regardless the width of the input trigger. One example of one shot multivibrator circuit is shown in the following schematic diagram, which uses LM139 as the main active component: The width […]


Power FET Lamp Flasher

As an alternative to bipolar transistor, a lamp flasher can be built by using two power FETs.  Like other flasher circuit, this circuit alternately switch the two lamps off and on.  It is based on a simple astable multivibrator that formed by the two power FETs.  To modify the flashing rate, just remember that flash […]


LM139 One Shot Multivibrator/Timer

One shot multivibrator circuit is also known as monostable multivibrator or timer. The function of such circuit is simply produce a pulse strobe with a fixed width, regardless of the pulse width of the triggering input.  Below is the circuit’s schematic diagram of simple one shot multivibrator uses one section of an LM139 comparator. The […]


LM139 One-Shot Multivibrator

The circuit below is a one-shot multivibrator. One shot multivibrator is also known as monostable multivibrator, or timer. The main function of such circuit is producing a fixed width pulse. The width of this pulse is determined by the component value selection at the time of designing the circuit. The main component of this circuit […]


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