[volt-nuts] Cool looking old stuff

[Robert Atkinson]

That is a "chopper" basically a high speed relay mechanically tuned to operate with mimimum contact bounce, normally at a specfic frequency. They were replaced by neons and resistive photo cells, FETs and then IC's 
Google "chopper Amplifier"
 
Robert G8RPI


________________________________
From: Joseph Gray <jgray at zianet.com>
To: Discussion of precise voltage measurement <volt-nuts at febo.com> 
Sent: Friday, 9 August 2013, 4:44
Subject: [volt-nuts] Cool looking old stuff


I'm helping the local surplus guy by going through some old gear and
checking it over. Sometimes I find something useful :-)

I just took apart a Millivac Instruments MV-37B DC Differential Voltmeter,
mostly because I was curious to see what was inside (I haven't powered it
on yet). Most of what I saw was not very impressive, but one item stood
out. Take a look at the two pictures.

https://dl.dropboxusercontent.com/u/19599147/Millivac%20-%20Rear.jpg

https://dl.dropboxusercontent.com/u/19599147/Millivac%20-%20Closeup.jpg

Joe Gray
W5JG
_______________________________________________
volt-nuts mailing list -- volt-nuts at febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts
and follow the instructions there.