Electronics > Beginners
MPSA70 PNP Transistor
dcbrown73:
Hey all,
I'm assembling an Elenco XP-720 power supply kit. There is a MPSA70 PNP transistor and after soldering it in. I wanted to ensure I didn't create any bridges. So I used my DMM's continuity tester and I show continuity between all three legs. I don't (even using a magnifying glass) see any bridges, so I wanted to ask if this positive continuity test is correct?
Seekonk:
I had to look twice when I saw that. We used to design with that transistor and I don't remember it as being able to take that much current. Well, it is a very low voltage. You should be seeing what passes for continuity on all three legs.
Emo:
Hi reading near to zero ohm is correct. This transistor is taking care of the current protection. As the values of th resistors in the circuit are very low it is hardly possible to read the values under normal situations
Regards, Eric
dcbrown73:
--- Quote from: Seekonk on August 16, 2019, 04:00:37 pm ---I had to look twice when I saw that. We used to design with that transistor and I don't remember it as being able to take that much current. Well, it is a very low voltage. You should be seeing what passes for continuity on all three legs.
--- End quote ---
When I test it with the continuity tester, I get the following:
* Emitter -> Base: 3.1 ohm
* Emitter -> Collector: 5.8 ohm
* Base -> Collector: 2.9 ohm
dcbrown73:
--- Quote from: Emo on August 16, 2019, 04:27:14 pm ---Hi reading near to zero ohm is correct. This transistor is taking care of the current protection. As the values of th resistors in the circuit are very low it is hardly possible to read the values under normal situations
Regards, Eric
--- End quote ---
Thank you!
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