what is Iceo in common emitter configuration in hindi
Answers
In common emitter configuration, base is the input terminal, collector is the output terminal and emitter is the common terminal for both input and output. That means the base terminal and common emitter terminal are known as input terminals whereas collector terminal and common emitter terminal are known as output terminals.
In common emitter configuration, the emitter terminal is grounded so the common emitter configuration is also known as grounded emitter configuration. Sometimes common emitter configuration is also referred to as CE configuration, common emitter amplifier, or CE amplifier. The common emitter (CE) configuration is the most widely used transistor configuration.
In common emitter configuration, the emitter terminal is grounded so the common emitter configuration is also known as grounded emitter configuration.
The common emitter (CE) amplifiers are used when large current gain is needed.
The input signal is applied between the base and emitter terminals while the output signal is taken between the collector and emitter terminals. Thus, the emitter terminal of a transistor is common for both input and output and hence it is named as common emitter configuration.
The supply voltage between base and emitter is denoted by VBE while the supply voltage between collector and emitter is denoted by VCE.
In common emitter (CE) configuration, input current or base current is denoted by IB and output current or collector current is denoted by IC.
The common emitter amplifier has medium input and output impedance levels. So the current gain and voltage gain of the common emitter amplifier is medium. However, the power gain is high.
To fully describe the behavior of a transistor with CE configuration, we need two set of characteristics – input characteristics and output characteristics.
Input characteristics
The input characteristics describe the relationship between input current or base current (IB) and input voltage or base-emitter voltage (VBE).
First, draw a vertical line and a horizontal line. The vertical line represents y-axis and horizontal line represents x-axis. The input current or base current (IB) is taken along y-axis (vertical line) and the input voltage (VBE) is taken along x-axis (horizontal line).
To determine the input characteristics, the output voltage VCE is kept constant at zero volts and the input voltage VBE is increased from zero volts to different voltage levels. For each voltage level of input voltage (VBE), the corresponding input current (IB) is recorded.
The input characteristics describe the relationship between input current or base current (IB) and input voltage or base-emitter voltage (VBE).
A curve is then drawn between input current IB and input voltage VBE at constant output voltage VCE (0 volts).
Next, the output voltage (VCE) is increased from zero volts to certain voltage level (10 volts) and the output voltage (VCE) is kept constant at 10 volts. While increasing the output voltage (VCE), the input voltage (VBE) is kept constant at zero volts. After we kept the output voltage (VCE) constant at 10 volts, the input voltage VBE is increased from zero volts to different voltage levels. For each voltage level of input voltage (VBE), the corresponding input current (IB) is recorded.
A curve is then drawn between input current IB and input voltage VBE at constant output voltage VCE (10 volts).
This process is repeated for higher fixed values of output voltage (VCE).
When output voltage (VCE) is at zero volts and emitter-base junction is forward biased by input voltage (VBE), the emitter-base junction acts like a normal p-n junction diode. So the input characteristics of the CE configuration is same as the characteristics of a normal pn junction diode.
The cut in voltage of a silicon transistor is 0.7 volts and germanium transistor is 0.3 volts. In our case, it is a silicon transistor. So from the above graph, we can see that after 0.7 volts, a small increase in input voltage (VBE) will rapidly increases the input current (IB).