AC power on front panels

jpero at jpero at
Sat Jan 14 11:02:22 CST 2006

> On 1/15/2006 at 8:59 AM Dave Brown wrote:
> >For a practical implementation of this sort of arrangement see the 
> >circuit here-
> >
> >
> h%20.pdf
> Very nice job, particularly using the grounded/earthed neutral as the
> return.  Here in the USA, one side of the 120vac is tied to the third prong
> of the mains receptacle in the distribution panel, so this would also be a
> way to avoid tying into an incorrectly-wired receptacle (more common than
> you'd think!). 
> Cheers,
> Chuck

Chuck is correct, this is major reason for using standby transformers 
(AC or SMPS) to provide low current power for power controlling the 
main power.

To other one who did this modifcation on a radio equipment and very 
low current control of the SSR relay,  find a cheap LED small digital 
alarm clock, uses 1" cube transformer and is wired.  Majority of 
these are not on the PCB board and ready to use, cut a small area of 
PCB to get diode(s), cap for DC output where transformer wires are 
soldered on. Usually 100mA, 16 to 12VAC.  Add a fuse for the mains 
side of transformer and another fuse after it.

Cheers, Wizard

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