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Crixan
Aug 10, 2010, 02:56 PM
Hello,
I have limited experience when dealing with transistors and have been having difficulty with one example in particular.

I have a NTE2308 transistor that I am trying to pass 300V from the collector to the emitter but when less than 7V is used to switch the transistor at the base, nothing happens.

I have been able to switch the transistor using the same voltage at the base but using 9V across the collector to turn on a small LED, so I know that the transistor works but I can not figure out why it will not work with a higher voltage.

Both configurations are essentially the same in that I have both voltage sources coming from the positive terminal, going through the transistor, then leaving to ground.

Please let me know if you need any additional information.

Thank you.

KISS
Aug 11, 2010, 01:12 AM
Data sheet is here: http://www.nteinc.com/specs/2300to2399/pdf/nte2308.pdf

Voltages are relatively meaningless since transistors are current devices.

What is Ib? (e.g. Base resistor and voltage source)
Hfe is about 16
What's the load and supply voltage?

Crixan
Aug 11, 2010, 06:53 AM
The smallest base resistor I have been using has been 22 ohm and the voltage going to the base I have measured is at most 0.22V.

I would like to give some additional information to explain the low voltage.

I am using two 555 timers in series to generate a timed pulse that is sent to the base of the NTE2308 transistor. I am using a 9V battery as a voltage source for both timers. The 22 ohm resistor is placed between the final 555 timer output and the base of the transistor.

I believe I measured the voltage correctly, but that seems like a very small voltage.

Crixan
Aug 13, 2010, 07:17 PM
I wanted to give a quick update so this topic can be closed. I was able to figure out that I bought the wrong transistor and was able to solve my problem with another approach.

Thank you KISS for your help.

KISS
Aug 13, 2010, 07:24 PM
Thought so.