How does a monostable multivibrator produce a single pulse of fixed width?
1 Answer
A monostable multivibrator, also known as a one-shot or single-shot multivibrator, is an electronic circuit that generates a single pulse of fixed width in response to an external trigger or input signal. The output pulse width is determined by the circuit's components and is not affected by the duration of the trigger input.
The basic concept behind a monostable multivibrator involves using an unstable state (or quasi-stable state) in the circuit that is triggered into a stable state when an external signal is applied. Once triggered, the circuit will remain in this stable state for a fixed duration before automatically returning to its original unstable state. During this period, it produces a single output pulse.
Here's a general explanation of how a monostable multivibrator works:
Unstable state: Initially, the multivibrator is in an unstable state where it is neither at its logic high nor logic low output state. It could be in an indeterminate or unpredictable state.
Triggering: When a trigger signal (a positive or negative edge) is applied to the trigger input, it causes the multivibrator to transition from the unstable state to a stable state. The trigger input can be a manual switch, a sensor output, or any other appropriate signal.
Capacitor charging: Upon triggering, a capacitor starts to charge or discharge (depending on the specific design of the circuit). This capacitor charging or discharging process determines the duration of the stable state and hence the output pulse width.
Fixed time period: The time it takes for the capacitor to charge or discharge to a certain threshold level defines the width of the output pulse. This time period is controlled by the values of resistors and capacitors used in the circuit.
Stable state: During the stable state, the multivibrator holds its output at a specific logic level (high or low) for the fixed time period determined by the charging or discharging of the capacitor.
Automatic return: After the fixed time period elapses, the multivibrator automatically returns to its initial unstable state, waiting for the next trigger signal to repeat the process.
In summary, a monostable multivibrator uses a triggered transition from an unstable state to a stable state, controlled by a capacitor charging or discharging process, to produce a single pulse of fixed width. The width of the pulse is determined by the values of resistors and capacitors in the circuit and is independent of the duration of the trigger signal.
The basic concept behind a monostable multivibrator involves using an unstable state (or quasi-stable state) in the circuit that is triggered into a stable state when an external signal is applied. Once triggered, the circuit will remain in this stable state for a fixed duration before automatically returning to its original unstable state. During this period, it produces a single output pulse.
Here's a general explanation of how a monostable multivibrator works:
Unstable state: Initially, the multivibrator is in an unstable state where it is neither at its logic high nor logic low output state. It could be in an indeterminate or unpredictable state.
Triggering: When a trigger signal (a positive or negative edge) is applied to the trigger input, it causes the multivibrator to transition from the unstable state to a stable state. The trigger input can be a manual switch, a sensor output, or any other appropriate signal.
Capacitor charging: Upon triggering, a capacitor starts to charge or discharge (depending on the specific design of the circuit). This capacitor charging or discharging process determines the duration of the stable state and hence the output pulse width.
Fixed time period: The time it takes for the capacitor to charge or discharge to a certain threshold level defines the width of the output pulse. This time period is controlled by the values of resistors and capacitors used in the circuit.
Stable state: During the stable state, the multivibrator holds its output at a specific logic level (high or low) for the fixed time period determined by the charging or discharging of the capacitor.
Automatic return: After the fixed time period elapses, the multivibrator automatically returns to its initial unstable state, waiting for the next trigger signal to repeat the process.
In summary, a monostable multivibrator uses a triggered transition from an unstable state to a stable state, controlled by a capacitor charging or discharging process, to produce a single pulse of fixed width. The width of the pulse is determined by the values of resistors and capacitors in the circuit and is independent of the duration of the trigger signal.