SSR question

Sure, there are the TRAIC SSR bricks that take 4 to 32VDC to switch - and can handle tens of amps.

Of course you need some power to enable that stuff to run - perhaps a capacitor/resistor driven supply that sucks a tiny amount of current from the power line to enable the drive circuit?

John :-#)#

There is a commercial module used by electricians to control a light (AC Powered) by opening and closing a reed switch actuated by a magnet installed in the top edge of a closet door. I have one in my house.

Joe Gwinn

Yes, I'd need another isolated ACline power supply to make the drive voltage for the SSR.

The alternative is to do what is common, have a giant power inlet block on the back (IEC, emi, fuses, big switch) and run that into my

There should be several models to choose from. I used them in the early

Then there are the MOC30xx opto-coupled triac drivers. I used several of those in a one-off product for the state racing association.

I think Piotr Wyderski posted a cool looking circuit using a small hf pulse transformer as isolation and coupling. Shorting the isolated LV side loaded or stopped an oscillator or something.

The 1960s GE SCR manual showed ways to do that too but using 50/60Hz transformers which are now not cost effective.

You could use a little generator - the EnOcean wireless wall switches do that to avoid using a battery. When you press it, the mechanical energy from your finger powers a tiny generator and powers the transmitter (either Bluetooth or another standard).

If someone would package just the button part that does the generating, leaving off the radio, it might well make enough power to turn on a SSR for a cycle or two, which could then power the thing up properly.

Reminds me of an old telephone ringer magneto that I had as a kid. It packed a pretty good shock.

How about a stepper motor with a knob? They make good generators.

Some people sell a small potted PCB-mount brick that's an AC-line powered power supply. But I'd have to design a PCB and run line voltage into it.

Some biggish universal-input metal-box power supplies have a contact-closure enable input. May as well use one of those, even thought I only need a few watts.

The product is a high-voltage pulse generator, probably a detonator or something. We don't know.

One thing to look out for, is the robustness against spurious turn-on (add snubber).

Also, if you draw more than just low power, look out for the zero crossing distortion. That might result in failing to comply with conducted emission tests.

I did a design on a 650W heater with several outputs, and in that one we had to roll our own driver, to make sure the Triacs was kept on during the zero crossing. One design implementation had back to back FETs.

Two windings of a stepper could be combined to make a positive voltage when spun clockwise and negative if spun CCW. That can drive a single-coil latching relay.

The mechanical solution used in a number of older HP test equipment pieces (and probably some other stuff) is put the switch set back on the main PCB and the front panel switch connects to a long plastic rod which pushes it indirectly.