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How do you test a NPN SMD transistor?
Hook the positive lead from the multimeter to the to the BASE (B) of the transistor. Hook the negative meter lead to the EMITTER (E) of the transistor. For an good NPN transistor, the meter should show a voltage drop between 0.45V and 0.9V. If you are testing PNP transistor, you should see “OL” (Over Limit).
How do you know when a transistor is bad?
A bad transistor can sometimes be detected by its partly burned or distorted appearance, but more often there is no visible indication. One approach to troubleshooting is to substitute a known good component, but that is a costly way to go.
What are the input characteristics of an NPN transistor?
Also, there is a voltage drop between the Base and the Emitter terminal of about 0.7V (one diode volt drop) for silicon devices as the input characteristics of an NPN Transistor are of a forward biased diode.
What makes a bipolar NPN transistor a good amplifying device?
The value of β can be large up to 200 for standard transistors, and it is this large ratio between Ic and Ib that makes the bipolar NPN transistor a useful amplifying device when used in its active region as Ib provides the input and Ic provides the output. Note that Beta has no units as it is a ratio.
What is the relationship between base and emitter in NPN?
The voltage between the Base and Emitter ( VBE ), is positive at the Base and negative at the Emitter because for an NPN transistor, the Base terminal is always positive with respect to the Emitter. Also the Collector supply voltage is positive with respect to the Emitter ( VCE ).
What are the properties of a bipolar junction transistor?
One of the most important properties of the Bipolar Junction Transistor is that a small base current can control a much larger collector current. Consider the following example. A bipolar NPN transistor has a DC current gain, ( Beta) value of 200. Calculate the base current Ib required to switch a resistive load of 4mA.