Design and Build a Simple Bistable Multivibrator Circuit Using Op-amp

A bistable multivibrator, commonly known as a flip-flop, is a switching circuit that has two stable states. In this analog implementation, an LM358 operational amplifier is configured with positive feedback, allowing it to act as a comparator with hysteresis (a Schmitt trigger). Because of the positive feedback network using 10K resistors, the op-amp's output is driven and held firmly at either positive or negative saturation depending on the differential input voltage. The dual polarity power supply provides both positive and negative rail voltages, enabling the op-amp output to swing symmetrically between high and low voltage states. Two tactile switches are integrated into the input stage to allow manual triggering; pressing one switch forces the non-inverting input high or low relative to the reference, causing the op-amp output to abruptly flip to the opposite stable state. The 10nF capacitor helps stabilize the switching action and filter out high-frequency noise during transitions. A 100R resistor is placed at the output to limit current, which can be connected to indicator LEDs or monitored using an oscilloscope. Unlike astable multivibrators that oscillate continuously or monostable circuits that time out, this bistable circuit remains indefinitely in its current state until an external trigger from one of the tactile switches forces a transition, making it fundamentally useful for basic memory and latching operations.