Draw and explain monostable multivibrator.

A Monostable Multivibrator, also known as a one-shot multivibrator, is a non-sinusoidal waveform generator that is used in timing and flip-flop applications. The monostable multivibrator has only one stable state (hence the name monostable) and it generates a single output pulse when it is triggered externally.

The circuit of a monostable multivibrator using an Operational Amplifier (Op-Amp) is shown below:

    +Vcc
     |
     |
     R1
     |
     +-----------------+
     |                 |
     |                 |
    -|+       R2       |
     |                 |
     |                 |
     +-----------------+
     |                 |
     |                 |
     |                 |
    -|-       C1       |
     |                 |
     |                 |
     +-----------------+
     |
     |
    -Vcc

In the above circuit, the Op-Amp is configured as an inverting comparator. The non-inverting input (+) is connected to ground (0V) and the inverting input (-) is connected to a voltage divider network formed by resistors R1 and R2. The output of the Op-Amp is fed back to the inverting input through a capacitor C1.

When the circuit is powered, the output of the Op-Amp is at its positive saturation level (+Vcc). The voltage at the inverting input is zero because the capacitor C1 is initially uncharged. Since the voltage at the non-inverting input is higher than the voltage at the inverting input, the output of the Op-Amp remains at +Vcc.

When a negative trigger pulse is applied to the non-inverting input, the output of the Op-Amp switches to its negative saturation level (-Vcc). This causes the capacitor C1 to charge through resistor R2. The voltage across the capacitor increases exponentially with time and eventually reaches the voltage at the non-inverting input. At this point, the output of the Op-Amp switches back to +Vcc and the capacitor starts to discharge through resistor R2.

The duration of the output pulse is determined by the time constant of the R2-C1 network and can be calculated using the formula:

T = 0.693*R2*C1

where:

• T is the duration of the output pulse,
• R2 is the resistance,
• C1 is the capacitance.

The monostable multivibrator is used in applications where a single pulse is required for a known period of time. Examples include timers, frequency dividers, and pulse position modulators.

Here is a table summarizing the key points:

Parameter	Description
Stable State	One
Output Pulse	Single
Trigger	External
Pulse Duration	Determined by R2 and C1
Applications	Timers, Frequency Dividers, Pulse Position Modulators