Archive for the ‘S.Y.B.Sc.(Physics)’ Category
The Basic Common-Base Amplifier,CB
Circuit Description: As shown in above circuit, PNP transistor is connected with emitter-base PN junction as forward bias by VEE whereas collector-base diode is reverse-biased by Vcc. AC signal is given by the source Vs through resistance Rs and output voltage is obtained across collector and base as voltage Vo’. Two-Diode Analogy of CB Amplifier: [...]
Transistor Collector Characteristics for CE Amplifier
Since base is narrow and collector is heavily doped with respect to the base, current can flow in the collector circuit though collector-base diode is reverse bias. The amount of collector current depends on how well base-emitter junction is forward bias. Thus large the forward bias VBE and the base current IB, larger will be [...]
Tow-Diode Analogy For A Transistor and Its Input Characteristics
As shown in above circuit transistor consist of two PN junctions, so that the transistor can be thought of as two diodes- in this case back-to-back position. Diode point outward as arrow on the emitter lead of the NPN transistor. In normal amplifier, as shown in above circuit the base-emitter junction is always forward bias [...]
Basic Transistor Amplifier
(1) Basic NPN common emitter amplifier showing current and voltage Note:(1) please read text in red as subscript. (2) Underline word or sentence in a blue color shows the link. Circuit Description: As shown in the above circuit diagram, the input ac signal Vs is given through resistance Rs to the base of transistor. [...]
S.Y.B.Sc.(Physics)
Comparison o f CE Amplifier with Triod Valve: The main difference between transistor and triode is that transistor is a current controlled device whereas triode is a voltage controlled device. Working of Basic NPN common emitter amplifier: (Click on the following image for working of CE amplifier and two diode analogy of a transistor)
