Introduction to design features of base ground circuit

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Introduction to design features of base ground circuit

Posted Date: 2024-02-06

Base ground circuit: Mainly used as a high-frequency amplifier circuit, or oscillation circuit, which has the characteristics of low input impedance and high output impedance. There is only voltage amplification, no current amplification, but current following. The input resistance is small, and the output resistance is related to the collector resistance. It has good high-frequency characteristics and is often used in high-frequency or wide-band low input impedance situations. It also has the function of potential shifting in analog integrated circuits.

Characteristics of base ground circuits

A base-to-ground circuit is a common amplifier circuit configuration in which the base of an amplifier tube (such as a transistor) is connected to ground (or a reference voltage). The following are several characteristics of base ground circuits:

1. Simplicity: The base ground circuit has a simple structure and is easy to design, implement and understand. It only needs to connect the base of the amplifier tube to ground and does not require additional circuit components.

2. Strong common-mode suppression capability: The base ground circuit has better suppression capability on the common-mode component of the input signal. Common mode signals refer to signals that are applied to two input ports at the same time. Their magnitudes and changing trends are the same. Since the base in a base-to-ground circuit is connected to ground, the common-mode component will be quickly rejected directly through the ground path.

3. Higher input impedance: The input impedance of a base-grounded circuit is usually higher and puts less load on the signal source. This means that the input signal source does not need to provide excessive current, thereby reducing the burden on the signal source.

4. Lower output impedance: The output impedance of a base-to-ground circuit is usually lower, providing lower resistance at the output. This allows the output signal to drive larger loads while maintaining better signal integrity.

5. Controllable amplification gain: By adjusting the bias voltage and current of the amplifier tube, the amplification gain of the base-grounded circuit can be controlled. This gives the grounded base circuit some flexibility in amplifying signals within a specific frequency range.

Although base-ground circuits have many advantages, there are some limitations to be aware of. For example, it has certain limitations on the dynamic range of the input signal, and the bias voltage of the amplifier tube needs to be set appropriately to avoid distortion.

Review Editor: Huang Fei

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