Transistors

rr

Hello,

Is it possible to limit the voltage that passes through a transistor by increasing the value of the resistor back??? I have done this in the past but·I feel like it is not really the right way to do things. In the past situation·I was using tip 29a. However,·I recently tried to do this with a tip 120 and the circuit acted really weird and didnt really work. I figured it was because of the darlington setup in the tip 120.


Thanks for the help...
rr

rr

oops I mean:
Is it possible to limit the current that passes through a transistor by increasing the value of the resistor back???

Mike Green

What do you mean by "resistor back"?

Normally you would limit the current through a transistor by using a resistor or other load impedance. This is used to limit the base current and to limit the collector current (different amounts ... different resistors).

Ugha

Did you mean voltage or current?

Perhaps a Voltage divider?

rr

I am talking abou the resistor between the stamp output pin and the base of the transistor.

LoopyByteloose

Yes, very often a 330 ohm resistor is put between the Stamp output pin and a transistor in order to protect the Stamp's I/O from damage. In some cases, you might see values that are in the thousands of ohms. That works too and can save on overall power consumption.

Transistors have 3 legs: the Emitter, the Collector, and the Base. The Base is one that is used for control.

5 volts/ 330 ohms = .0151 amps or 15.1 millamps. You really don't want to go much higher than 20-25ma.

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