Reversing Polarity for NPN Transistor Testing per MIL-STD-750-3 Standards?

I just want to check my sanity...

I am going to be testing some transistors in a lab very soon per the above mil std. The test methods range from Vce, Vbe, hfe and the breakdown voltages that are listed on the datasheet. The transistor at this point is irrelevant.

Here's what I need to understand. According to the mil std, the circuits are all drawn for PNP trnsistors in one configuration. That's fine. However, I will most,likely be testing NPN transistors. So, if I understand this right, all I need to do is reverse the polarity of the sources and test equipment (ammeter, voltmeter) in order to correctly perform the tests per this std. Is this right?

Yes,
see MIL-STD-750 PARAGRAPH
4.3.3 Test circuits. The circuits shown are given as examples which may be used for the measurements. They are not necessarily the only circuits which can be used but the manufacturer shall demonstrate to the Government that other circuits which he may desire to use will give results within the desired accuracy of measurement. Circuits are shown for PNP transistors in one circuit configuration only. They may readily be adapted for NPN devices and for other circuit configurations.

Hi,

Technically that is what I would do. I would reverse the polarity of the source. For a npn, it should be positive. Just keep in mind the orientation of the ammeter and voltmeter..

I have an additonal question about this now that I am in the middle of ramping up the testing.

In some of the methods (ie. 3071 and 3076.1) there is a switch and voltage source in parallel with what I believe to be battery, both connected across Vbe. I don't quite follow this.

Is the battery used for the static test and the switch for the pulse test, or are supplies used for testing either way? In that case, I have no idea how to perform this test as the circuit no longer makes any sense.

What is your take on this?

Timothy,
Yes , it is a little confusing (3071 and 3076)
the switch just represents pulsing the transistor base current to minimize the power dissipation that would change the measurement so that you don't have to heat sink the device.
Typical transistor curve testers do that at 100-300 microseconds to avoid this problem

take a look at this link
http://www.ece.rice.edu/~jdw/data_sheets/tek571c.pdf

Also if you are getting into to full scale transistor testing Agilent/Keysight makes a B1505A or Keithley/Tektronics or National Instruments makes similar devices
Tom Terlizzi