[GreenKeys] DIY loop supply?

[Harold Hallikainen]

> I’m thinking of building one of these for bench top experimentation
> purposes that I can also use as a teletype loop supply if needed. Anyone
> see something I’m not seeing at first glance that indicates it might not
> work as a loop supply?
>
> I can buy one (actually already did thanks to earlier suggestion from
> several greenkeyers), but I thought it might be fun to build one.
>
>
> https://tinyurl.com/r9vj7lc
>
> Now I need to look in the mirror and ask “really? You think have time
> for this?”   I’m afraid of the answer :-)
>
>
>
> Paul
> W2TTY


Interesting design. Looks good for vacuum tube experimentation, but seems
like overkill for a loop supply. A transformer, rectifier, capacitor, and
power resistor to set the current is probably sufficient for a loop
supply. That photo of the Associated Press box I sent earlier is typical.
It had a transformer, selenium rectifier, capacitor, and resistor. Since
line voltage variation is minimal, and load current is minimal, it doesn't
appear we need any regulator.

Harold


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