The three electrodes and working area of ​​the transistor
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The three electrodes and working area of ​​the transistor

Posted Date: 2024-02-04

What control element does a transistor consist of?

A transistor is composed of three main components, namely drain (Collector), base (Base) and emitter (Emitter). A transistor is a semiconductor device used to amplify and control electrical current. It is one of the most important components in modern electronic technology.

A transistor works by controlling the base current to control the flow of current between the drain and emitter. When the base current is small, the transistor is off and almost no current flows through it. When the base current increases, the transistor begins to conduct, and current flows from the drain to the emitter, completing the amplification operation.

Transistors have amplification and switching characteristics and are therefore widely used in electronic devices, such as amplifiers, computers, communication equipment, etc. Its small size, low power consumption and high reliability make transistors an indispensable control component in modern electronic technology.

What are the three electrodes of a transistor?

The three electrodes of a transistor are drain (Collector), base (Base) and emitter (Emitter). The function of these three electrodes is to control the flow of current and amplify the signal.

The drain is located on one side of the transistor and is the output terminal for electrical current and the negative terminal of the electronic device. When current flows from the drain of a transistor, the drain electrode absorbs electrons and outputs them to an external circuit.

The base is located in the middle of the transistor and is key to controlling the flow of current. By adding or subtracting a voltage to the base electrode, the on and off states of the transistor can be controlled. When the base current increases, the transistor becomes conductive and current flows from the drain to the emitter.

The emitter is on the other side of the transistor and is the input terminal for electrical current and the positive terminal of the electronic device. The emitter receives the base current and injects it into the transistor, thereby controlling the flow of current between the drain and emitter.

The interaction of the three electrodes gives the transistor the function of amplifying and controlling current, and also makes the transistor an essential component in modern electronic devices.

Three working areas of a transistor

The transistor has three main working regions, namely cut-off region, active region and saturation region.

1. Cut-off region: When the base current of the transistor is small, the transistor is in the cut-off region, also called the turn-off region. In this region, the transistor is off and almost no current flows through it. The flow of current from drain to emitter is blocked.

2. Amplification zone: When the base current gradually increases, the transistor enters the amplification zone. In the amplification region, the transistor begins to conduct, and the amplification effect of the current gradually becomes apparent. Changes in the base current will cause changes in the current from the drain to the emitter, thereby amplifying the current.

3. Saturation region: When the base current increases further, the transistor enters the saturation region. In the saturation region, the transistor is fully conductive and current flows through the transistor from drain to emitter without restriction. When in the saturation region, the transistor cannot amplify the current any further.

Switching between these three working areas is achieved by adjusting the control voltage and base current of the transistor. Different operating regions have different properties and uses, allowing transistors to perform amplification and switching control functions in electronic circuits.

Review Editor: Huang Fei


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