Astable Multivibrator (Oscillator)

Posted on Feb 7, 2014

This circuit is an astable multivibrator, or oscillator. The two transistors are cross-coupled in such a way that the circuit switches back and forth between two states. In one state, the base of Q1 is about one diode drop above ground, allowing a base current to flow. This keeps Q1 switched on, in saturation mode, allowing a current to flow throu

Astable Multivibrator (Oscillator)
Click here to download the full size of the above Circuit.

gh the collector, keeping Q1`s collector voltage low, and discharging C1. Q2 is switched off, because its base voltage is not high enough to switch it on. As the collector current into Q1 charges C1, the base voltage for Q2 goes up, until it is high enough to switch on Q2, causing a current to flow through its collector, which drops the collector voltage (the current causes a voltage drop across the resistor above it). The right side of C2 has dropped, but the voltage across it hasn`t changed, so this causes Q1`s base voltage to drop below ground, switching it off.

Leave Comment

characters left:

Related Circuits

  • New Circuits



    Popular Circuits

    Do Oscillation Building Circuit by Your Self!
    medium power fm transmitter circuit
    adding audio to arduino projects
    DC Power Supply 9 volt using TIP31 transistor
    working principles of motor control
    LM741 IC for Light Dark Sensor Circuit
    555 ramp generator
    Improving the MICOR Receiver for 435-450 MHz
    Precise Camera Panning with Stepper Motors