"Gareth Magennis"
"Phil Allison"


I recently bought some TIP35C transistors from Farnell UK. Just before
I fitted one to an amplifier I thought I'd just check the pinouts.
Good job I did because instead of BCE they measured BEC.


** That is just not possible.

The middle leg is always the collector and metal tab used for
heatsinking.

FFS - get an ohmmeter and verify that simple fact.

Seems your dopey microprocessor ( ie software) based POS has gone ape and
confused Collector with Emitter.



I did suspect my dopey checker, but even with a fresh battery it ALWAYS
reads EXACTLY the same,


** ROTFL - since when is THAT any reason to trust it ?????

" It must be right cos it always tells the SAME lie "

Wot an idiot you are.


which is: 3 of them measure BEC with an Hfe of 5, the other one BCE with
an Hfe of 20.

** No fooling.

BJTs have very low Hfes if C and E are reversed.

Like 2 or 3 instead of 100 or 200.

They *also* show very low readings if the meter is no ****ing good.

See how that might be confusing ???


(All tabs connect to centre pin)


** Then there is simply **NO** problem with the devices.
-------------------------------------------------------------------

YOU are the problem with your dopey meter that is not able to tests power
BJTs properly.

FYI Try it with a TV horizontal output transistor like the BU208.


The replacements I finally got from Farnell with a different batch code
measure an Hfe between 40 and 70.


** Testing the Hfe of *power transistors* is a whole DIFFERENT ball game
to small signal devices.

That is why I designed a special device just for power devices - published
as a project in Electronics Australia magazine in May 1988.

Test are done at a constant Ic of 0.6 amps instead of some fixed and way too
small Ib.

Results are spot on and match maker's data which follow the same idea.

Works fine with TV horizontal output devices, power darlingtons and any BJT
rated for high power.



I know Hfe is kind of meaningless on these types of checker voltages, but
was still wondering why the checker would give a different pinout result
rather than fail the device.

** Cos it is using the wrong approach for power BJT devices.

I suspect all 4 of the "old" transistors are faulty,

** ********.

You have a ******ing useless** meter that only works with those examples of
power BJT devices that exceed maker's specs at the low end of the Ic v Hfe
range.

Take a LOOK at some ACTUAL power BJT data sheets some time !!!!!!!!!

Hfe is NOT a constant !!!!!!!!!!!!



..... Phil