Retro Teardown: Electromagnetic Industries- Voltage/Frequency Meter

[FenderBender]

Hey guys,

This is an old voltage detection meter and has a built in frequency function. Very simple circuit and meter. It's dated 1974.

[Chet T16]

How awesome is that board?!

[FenderBender]

Awesome. LOL.

[tekfan]

Is there even a battery in that thing?

[FenderBender]

Nope. Didn't actually bother to see how it works but my bet is that there's some sort of rectification going on, which is why all the components are marked for such high voltages. A lot of high voltage going on.

[FenderBender]

How awesome is that board?!

Gotta love old school layout/trace style.

[Frangible]

Gotta love old school layout/trace style.

That style comes from the mask being laid out on transparent plastic sheets at large scale using thin sticky tape for the lines.  The tape had a certain minimum bending radius at which it would try to peel off the plastic, so it made for smoothly curved lines.  My wife was still doing that when I met her in 1990 - new boards were designed with CAD systems, but enough old board designs were still around to call for someone experienced with those materials.

[FenderBender]

Gotta love old school layout/trace style.

That style comes from the mask being laid out on transparent plastic sheets at large scale using thin sticky tape for the lines.  The tape had a certain minimum bending radius at which it would try to peel off the plastic, so it made for smoothly curved lines.  My wife was still doing that when I met her in 1990 - new boards were designed with CAD systems, but enough old board designs were still around to call for someone experienced with those materials.

Hey there's something I bet a lot of people don't know! Or atleast I didn't...