using a multimeter identify the terminal of a transistor. (this question is experimental based so kindly answered in proper manner as like as a lab equipment contain ( aim of experiments ,theory, apparatus use , precautions, and observations)
Answers
Answer:
Aim
To use a multimeter to:
(a) identify base of transistor
(b) distinguish between npn and pnp type transistors.
(c) see the unidirectional flow of current in case of a diode and an LED.
(d) check whether a given electronic component (e.g., diode, transistor or IC) is in working order.
Explanation:
Apparatus
A multimeter, transistors, npn and pnp, an IC (integrated circuit 7408 or 7432 each with 14 legs), a diode and an LED.
A transistor is a three terminal device. It can be regarded as a combination of two junction diode joined in an opposite manner such that the middle part is common to both. When an n-type of semi-conductor is sandwitched between two p-type of semiconductors, the transistor is p-n-p type but when p-type of semi-conductor, the transistor is npn transistor. Input section is forward biased and output section of a transistor is reversed biased. The base current is small but emitter and collector current is large. Ic = Ib + Ic.
(a) Identify the base: If one of the three terminals of the transistor is so chosen that conduction take place in both the cases when a multimeter is connected between the chosen terminal and either of the remaining two terminals, then the chosen terminal is the base.
(b) To find out whether the transistor is p-n-p or n-p-n: For conduction to be possible in both the above said cases, if the common terminal of the transistor has to be
connected to +ve, then the transistor is n-p-n type. But if the common terminal has to be connected to -ve for making the conduction possible in both the case, then the transistor is p-n-p type.
(c) Identifying an IC. An IC has minimum of eight legs. Most of the IC packages have flat back.
(d) A diode or an LED conducts only when forward biased and in reverse biasing, there is no flow of current.
(e) When a diode is in working order, it will allow the current to flow in one direction, when forward biased
Procedure
Use the selector switch and put the multimeter in ohm range (R).Insert the metallic end of the back lead in common terminal of the multimeter and that of the red in the terminal marked P.