On 09/17/2015 08:05 PM, krw wrote:
On Thu, 17 Sep 2015 20:16:17 +0100, "Ian Field"
wrote:


"DaveC" wrote in message
...
How's it measure?

(Or if it's dead, is there another one probably working that you can
test?)

Tim

Dead. Other with identical markings measure as NPN. What else to determine
from measurements?

You can usually distinguish the B/E junction because it will zener somewhere
around 5 - 8V ish.

You need to keep the test current pretty low - you can get ultra-efficient
LEDs that give a useable indication at only 2mA. Hook one of those up with
an A23 12V keyfob battery and a current limiting resistor.

InGaN (true) green LEDs are quite bright at only 1mA. They can be
seen at much less than that.


An ordinary 4-3/4 digit DVM on the lowest volts range (400 mV usually)
makes a poor man's picoammeter. The 10 megohm ones read 1 LSB (0.01 mV)
for 1 pA. Some of the older ones, where the lowest range doesn't have
the 10M resistor in parallel, can be much more sensitive than that.

You aren't going to hurt a transistor with a nanoamp of reverse base
current, and the measurement is pretty simple.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics

160 North State Road #203
Briarcliff Manor NY 10510

hobbs at electrooptical dot net
http://electrooptical.net