UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post - Circuit tracing

mark_in_manc · 13th Sep 2018, 10:33 am

Thanks for all these ideas.

So on a 15v ohms range Avo, forward bias will read about .7/15 of the way along from 0 ohms, and reverse bias will be Zener V./15 - so a 7.5v hypothetical Zener would give half-scale deflection?

I think I'm confused over the difference between a resistor between the probes (where R is fixed, and the i that flows due to battery and shunts happens to produce 7.5v across the probes) and a zener (where V is fixed...but does that mean i through the thing and therefore it's effective 'R' are the same as for the resistor example, assuming the shunts etc in the meter and the state of the battery are the same between the two tests? Sorry folks, I think this should be trivial but I'm a bit slow at the moment).

13th Sep 2018, 10:33 am	#11
mark_in_manc Octode Join Date: Nov 2011 Location: Manchester, UK. Posts: 1,875	Re: Circuit tracing - zener, or not zener? Thanks for all these ideas. So on a 15v ohms range Avo, forward bias will read about .7/15 of the way along from 0 ohms, and reverse bias will be Zener V./15 - so a 7.5v hypothetical Zener would give half-scale deflection? I think I'm confused over the difference between a resistor between the probes (where R is fixed, and the i that flows due to battery and shunts happens to produce 7.5v across the probes) and a zener (where V is fixed...but does that mean i through the thing and therefore it's effective 'R' are the same as for the resistor example, assuming the shunts etc in the meter and the state of the battery are the same between the two tests? Sorry folks, I think this should be trivial but I'm a bit slow at the moment).