View Single Post
  #9   Report Post  
Posted to sci.electronics.repair
Dave Plowman (News) Dave Plowman (News) is offline
external usenet poster
 
Posts: 43,017
Default Heathkit v7a vtvm battery

In article ,
Bryce wrote:
My v7a vtvm (built by a guy who looks like me but a lot younger)
uses a 1.5v battery for resistance measurements. I'm tempted
to replace it with a zener reference. Looks easy: the battery
is grounded on neg side, so is one side of the 6.3vac.


I guess we didn't have zeners fifty years ago. Dunno why Heath
didn't use several 1n34's in series (I think we DID have those!)
- thermal stability I suppose.


Must be more to it than that - the voltage from a dry cell varies by a
large amount over its life, hence the set zero facility.

--
*The problem with the world is that everyone is a few drinks behind *

Dave Plowman London SW
To e-mail, change noise into sound.