What causes the Early effect in BJT?

A large collector base reverse bias is the reason behind the early effect manifested by BJTs.

What is Early effect in transistor What are its consequences?

Early effect causes an increase in collector current. BJT’s are generally considered as current controlled current sources. As emitter current increases,collector current increases as well. Early effect causes collector current to change in accordance with the collector voltage.

What is Early effect or base width modulation in BJT?

Early effect or base width modulation: The early effect is the variation in the width of the base in a bipolar transistor due to a variation in the applied base-to-collector voltage. For example a greater reverse bias across the collector- base junction increases the collector-base depletion width.

How do you calculate the resistance of a BJT?

The output resistance of the common-emitter amplifier is just Rout = RC. To see this, consider Figure 5.40 on page 199 of Razavi.

What is punch through effect in BJT?

[′pənch‚thrü] (electronics) An emitter-to-collector breakdown which can occur in a junction transistor with very narrow base region at sufficiently high collector voltage when the space-charge layer extends completely across the base region.

What is Kirk effect?

Kirk effect; apparent base-width increase in a bipolar transistors caused by high concentration of carriers being swept from base to collector.

What is Early effect and punch through effect in BJT?

For the extremely large voltages, base width may be reduced to zero causing the voltage to breakdown in the transistor. This phenomena is known as punch through or reach through effect.

What is Early effect punch through and reach through?

Such action causes the effective base width ‘W’ to decreases. A phenomenon know as ‘Early Effect’ Punch-through (or) Reach -through If an excessive reverse-bias voltage is applied to the collector-base junction, the device breakdown may occur.

What is the output resistance of a BJT?

The ideal output impedance is zero; an amplifier with a low ouotput impedance can provide a larger output current without a significant reduction in the output voltage.

What is the input resistance of a BJT?

If it is a bipolar transistor (BJT), there is no actual input resistance. The current vs. voltage relationship of the Base terminal is not linear, so there is no specific number.

What is avalanche breakdown in BJT?

An avalanche transistor is a bipolar junction transistor designed for operation in the region of its collector-current/collector-to-emitter voltage characteristics beyond the collector-to-emitter breakdown voltage, called avalanche breakdown region.

What is base gummel number?

GB is the base Gummel number, which represents all the subtleties of BJT design that affect IC. The base (input) current, IB , is related to IC by the common-emitter current gain, βF . This can be related to the common-base current gain, αF .