Transistor Testing Circuit

Transistor Testing Circuit: In-Circuit Testing – A quick test to check if a transistor is operational can be performed while the device is still connected in a circuit. Consider Fig. 4-34, which shows a voltmeter connected to measure the transistor collector voltage (VC). The VC measurement is noted, then the base and emitter terminals are temporarily […]

Common Base Characteristics of BJT

Common Base Characteristics of BJT: Common-Base Connection – To investigate the Common Base Characteristics of BJT of a diode (a two-terminal device), several levels of forward or reverse bias voltage are applied and the resulting current levels are measured. The characteristics of the device are then derived by plotting the graph of current versus voltage. […]

Amplification in Transistor

Amplification in Transistor: Current Amplification in Transistor – We already know that a transistor can be used for current amplification. A small change in the base current (ΔIB) produces a large change in collector current (ΔIC) and a large emitter current change (ΔIE), [see Fig. 4-16(a) and (b)]. Rewriting Eq. 4-5, the current gain from the […]

Transistor Voltage and Current

Transistor Voltage and Current: The Transistor Voltage polarities for an npn transistor are shown in Fig. 4-10(a). As well as conventional current direction, the direction of the arrowhead indicates the transistor bias polarities. For an npn transistor, the base is biased positive with respect to the emitter, and the arrowhead points from the (positive) base […]