LooseCannon wrote:Hey guys,
I'm looking for a way to measure hfe on silicon NPN transistors (I don't have an HFE function on my DMM).
I've searched all over the web but only found ways to measure Germaniums which includes voltage leakage.
I did find this page:
http://sound.westhost.com/project31.htmWill the circuit on figure 1 work? He doesn't state the value of the resistor and what power supply should be used.
Any ideas?
Thanks
You should be able to use the circuit on R.G. Keen's website to measure the gains of NPN Silicon Transistors, since the circuit should work equally well because Ge and Si Transistors work in the same basic way, except that Si Transistors have leakages in nano-amps whereas Ge Transistors have leakages in micro-amps, which is about 1000 times more than Si Transistors, your gain readings will be higher though, I just checked out the link and there is a schematic for a suitable power supply, I wouldn't mind building the circuit up cause it looks like a useful bit of test equipment.......

It looks like the circuit in fig 1 should work fine.....
What these Transistor Tester circuits are doing is feeding a set amoumt of current into the base of the Transistor being tested, and they measure the amount of current flowing through the collector and compare the difference, if you want to get a bit more mathematical the current-gain (Hfe) of a Transistor, sometimes called the "Beta", is equal to the Collector-current divided by the Base-current, this is irrespective of what semiconductor material is used to make the transistor.......
Hope that helps.....

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