Educational program: Mechanic– electrician Titleof program: Technicaltraining II. class Transistor as anamplifier Workedout: Bc. Chumchal Miroslav Projekt Anglicky v odborných předmětech, CZ.1.07/1.3.09/04.0002 je spolufinancován Evropským sociálním fondem a státním rozpočtem České republiky.
Transistor as an amplification element • Description of transistor • Schematic marking • Connection of transistorin circuit, practical exercise • Specification • Description of connection • Control question
Description of transistor • The transistor is active electronic semiconductor element, which has amplification ability. It is created by couple of junctions PN. • Bipolar transistor has three outlets marked like B- base, K ( C )- collector and E- emitter. • This semiconductor element changing own resistance so that between E and C would not pass through bigger current, than is Beta multiple current, which pass through to the control electrode B. • Semiconductor transmitter is occurencing in two types NPN and PNP. Their function is similar, but they are different by opposite polarity. Where at the PNP current pass through by one direction, at the NPN type pass through by opposite direction.
Influence of elements on amplifier work • T – silicon transistor, amplifying bringing signal. • C1 – coupling capacitor separate direct- current voltage from alternating element. • C2 - coupling capacitor. • RC – influence of working point of transistor. • RE – If it is connection, it reduce reachable oscillation of output voltage. • R1, R2 – setting of working point of transistor. The more current pass through by divider, the more constant voltage is on base of transistor.
Practical exercise for students Make a connection of given scheme on contact field and compare function of transistor as a circuit breaker and as the amplifier. Explain the different?
Questions for students • 1.Question – Explain function of transistor. • 2.Question – Draw schematic mark PNP and NPN of transistor. • 3.Question – Replace transistor KC 508 by transistor series BC….
Literature used • Poznáváme Elektroniku I.,Václav Malina, Vydalo nakladatelství KOPP,České Budějovice, 1996 • www.google/Wikipedie - zesilovače • Vlastní poznámkový sešit