What is current gain for common-base and common emitter transistor?

Current gain in the common emitter circuit is obtained from the base and the collector circuit currents. Because a very small change in base current produces a large change in collector current, the current gain (β) is always greater than unity for the common-emitter circuit, a typical value is about 50.

What is current gain in common emitter configuration?

Current gain: It is the ratio of change in output current divided by change in input current. The common emitter configuration produces the highest current and power gain of all three transistor configurations.

Why base current is the input current in common emitter configuration?

So changes in the emitter current will change the base current and you will see a change in the collector current. Likewise for a common emitter amp the emitter’s voltage is fixed thus to change the base current you use the base as the input.

Why common-base configuration is not preferred to be used as amplifier?

The base is grounded for the signal although for biassing reasons, the DC potential will be above ground level. The common base amplifier configuration is not used as widely as transistor amplifier configurations. As a result, the voltage gain of a common-base amplifier can be very high.

What factors affect the current gain?

Temperature effects on current gain β: Temperature has a major effect on many bipolar transistor parameters, one of which is the current gain, β / hFE, etc. Frequency: The frequency of operation will have a marked effect on the value of current gain.

Why common emitter BJT configuration is used for amplification over other configuration?

Common emitter transistors are used most widely, because a common emitter transistor amplifier provides high current gain, high voltage gain and high power gain. This type of transistor gives for a small change in input there is small change in output.

What is the difference between common base and common emitter and common collector?

Bipolar Transistor Configurations Common Base Configuration – has Voltage Gain but no Current Gain. Common Emitter Configuration – has both Current and Voltage Gain. Common Collector Configuration – has Current Gain but no Voltage Gain.

Why common base configuration has no current gain?

Common Base Amplifier Voltage Gain Since the common base amplifier can not operate as a current amplifier (Ai ≅ 1), it must therefore have the ability to operate as a voltage amplifier. The voltage gain for the common base amplifier is the ratio of VOUT/VIN, that is the collector voltage VC to the emitter voltage VE.

Why a common emitter transistor is preferred over a common base transistor?

Common emitter circuit is preferred over a common base circuit in amplifiers because the resistance of the common emitter circuit is much less than that of the common base circuit. Also the power gain in the common emitter circuit is much higher than that in a common base circuit.

What is the gain of common emitter transistor amplifier?

Common emitter transistor amplifier gain. Another important factor is the gain level that can be achieved. There are two forms of gain that can be determined: current gain and voltage gain. The current gain for the common emitter amplifier circuit is denoted by the Greek symbol β. This is the ratio of collector current to base current.

What is common emitter configuration and common base configuration?

Common Emitter Configuration – It is the BJT configuration in which it behaves like an amplifier (it has both current and voltage gain). Common Base Configuration – It is the BJT configuration in which (it has Voltage Gain but no Current Gain).

What causes emitter current to be less than collector current?

When the emitter current flows into the base terminal and doesn’t perform as collector current. This current is always less than the emitter current which causes it. The gain of the common base configuration is always less than 1.

What is the current gain of the common base configuration?

When the emitter current flows into the base terminal and doesn’t perform as collector current. This current is always less than the emitter current which causes it. The gain of the common base configuration is always less than 1. The following formula is used to calculate the current gain of the CE (α) when the CB value is given i.e (β).