Is a BJT active or passive?
1 Answer
A **BJT (Bipolar Junction Transistor)** is an **active** device, meaning it requires an external power source to function, and it can amplify signals.
Here’s a detailed explanation:
- **Active Devices:** These devices, like transistors (BJTs, FETs), have the ability to control a large amount of current or voltage with a smaller input signal, essentially amplifying the signal. They do so by providing gain and requiring external power to operate. The BJT specifically relies on a voltage difference between its base and emitter to control current between the collector and emitter. When configured in various amplifier circuits, the BJT can take a small input signal and increase its power.
- **Passive Devices:** These include components like resistors, capacitors, inductors, and diodes. Passive devices do not provide gain or amplification. They typically dissipate energy (in the form of heat, for example) or store energy temporarily (like capacitors and inductors).
In a BJT, the current flowing through the collector and emitter is controlled by a much smaller base current, allowing it to act as an amplifier or switch in various circuits. Thus, due to its amplification capabilities, a BJT is considered an active device.
Here’s a detailed explanation:
- **Active Devices:** These devices, like transistors (BJTs, FETs), have the ability to control a large amount of current or voltage with a smaller input signal, essentially amplifying the signal. They do so by providing gain and requiring external power to operate. The BJT specifically relies on a voltage difference between its base and emitter to control current between the collector and emitter. When configured in various amplifier circuits, the BJT can take a small input signal and increase its power.
- **Passive Devices:** These include components like resistors, capacitors, inductors, and diodes. Passive devices do not provide gain or amplification. They typically dissipate energy (in the form of heat, for example) or store energy temporarily (like capacitors and inductors).
In a BJT, the current flowing through the collector and emitter is controlled by a much smaller base current, allowing it to act as an amplifier or switch in various circuits. Thus, due to its amplification capabilities, a BJT is considered an active device.