AppleColor RGB Monitor (IIGS) help?

[Chuck Guzis]

On 23 Apr 2009 at 19:21, Tony Duell wrote:

> If a transistor passed this test, you need more complex equipment to
> test it. Basically you bpass a small current trhough the base-emitter
> juction and see how it affects the collector current -- in other words
> you use the transisorr as am amplifier. Real enthuisats have a thing
> called a 'curve tracer' which does this automatically and plots one of
> a range of voltage-current or current-current traces on a CRT. But I
> find my Tekky 575 (such an instrument) rarely gets used when I'm
> faultfinding, the defective transsitor can be found with simpler
> tests.

Most currently available inexpensive DMMs that I've seen have the 
capability to check transistor hFE,  The last freebie I received with 
a parts order has that capability, a temperature probe, capacitance 
measurement and a frequency meter-and a backlit LCD display.  They 
just keep packing more and more into the same little hunk of silicon.

Where the two-diode transistor falls apart is in applicatons where 
Vce is less than Vbe.  The transistor works, but it's hard to 
rationalize why if you're using the "two diode" analogy.  One of my 
favorite Bob Pease columns:

http://electronicdesign.com/Articles/ArticleID/15690/15690.html

--Chuck