Which of the following multi vibrator is used as an oscillator without using triggering?

Explanation:

Astable Multivibrator as an Oscillator

Definition: An astable multivibrator is an electronic circuit that generates a continuous output of square wave oscillations without requiring any external triggering. It is essentially a free-running oscillator, which means it oscillates between its two unstable states indefinitely, producing a consistent and repetitive waveform.

Working Principle: The astable multivibrator operates by charging and discharging capacitors through resistors, which in turn switches the output states of the transistors or other switching devices used in the circuit. The time taken for the capacitors to charge and discharge determines the frequency of the oscillation. Since the circuit does not have any stable states, it continuously switches between its two states, hence producing a periodic output signal.

Advantages:

• Simple design and easy to construct using basic electronic components.
• Provides a stable and continuous square wave output without the need for external triggering.
• Widely used in timing applications, waveform generation, and clock pulse generation.

Disadvantages:

• The output frequency can be susceptible to variations in component values and power supply fluctuations.
• Not suitable for applications requiring precise frequency stability.

Applications: Astable multivibrators are commonly used in various applications such as LED flashers, pulse generation circuits, clock pulse generators, and in electronic devices where a continuous oscillating signal is required.

Correct Option Analysis:

The correct option is:

Option 2: Astable

This option correctly identifies the type of multivibrator that operates as an oscillator without requiring any external triggering. An astable multivibrator continuously oscillates between its two states, generating a periodic square wave output.

Additional Information

To further understand the analysis, let’s evaluate the other options:

Option 1: Bistable

A bistable multivibrator, also known as a flip-flop, has two stable states and requires external triggering to switch between these states. It is not used as an oscillator because it does not produce continuous oscillations on its own. Instead, it remains in one of its stable states until an external trigger is applied to change its state.

Option 3: Monostable

A monostable multivibrator has one stable state and one unstable state. When triggered, it temporarily switches to the unstable state and returns to the stable state after a predetermined time period. It is not used as an oscillator because it requires an external trigger to generate a pulse and does not produce continuous oscillations.

Option 4: Stable

This option is not a specific type of multivibrator. The term "stable" generally refers to the stability of a circuit or signal, but it does not describe a type of multivibrator. Therefore, it is not applicable in this context.

Conclusion:

Understanding the different types of multivibrators and their operational characteristics is essential for identifying their appropriate applications. An astable multivibrator, as explained, functions as a free-running oscillator that generates continuous square wave oscillations without the need for external triggering. This makes it suitable for various timing and waveform generation applications, providing a simple and effective solution for generating periodic signals.