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Which transistor?

A

Alistair

Jan 1, 1970
0
Hi,
I have a huge dilema here. Basicly its thus:

The outputs from a 4017 (5 stage Johnson Counter) are being fed into BFX 34
transistors (NPN),This part of the circuit works well. I want to drive two
12volt 21w lamps (so thats a total of 42watts and 3.5 amps of current. I
have got a TIP42A transistor that says its an PNP but it works as if its a
NPN for some peculiar reason?

Would someone out there help me find the most suitable setup for getting the
4017 to the bulbs, it is driving me nuts searching the RS website!

I drove relays from the BFX34's but with feedback, and Im limited for space
now on the second and final stage of my project, so driving the lamps using
transistors would be vey advantageous indeed.

Many many thanks

Alistair
 
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