Relay for 74HC-controlled outlet strip

Instead of using your regulated power to run a relay coil, consider using a phototriac-output optocoupler to drive a 120VAC relay. It has most of the good features of a solid-state relay without the complication of sucking half an amp from a power supply intended for CMOS.

An interesting idea...one that could easily remove the complexity on the DC side of things.

A 5VDC solid-state phototriac relay I'm looking at has the following phraseology in the data sheet: "No overvoltage absorption element is built in. Therefore, if the G3MC is connected to an inductive load, be sure to connect the overvoltage absorption element." I would guess that a coil relay is an inductive load. What would one use as an overvoltage absorption element?

Thanks PSM

Use X10. The life/home you save may be your own.

I did in fact mean 1250, not 12500, but I was talking about watts. No lightbulb, appliance, or computer PSU has ever been rated in VA. (This is odd to me, since from what I've read it's VA that applies to AC. Why are these things rated in watts?)

I'm looking at using the relay-switched strip with a few combinations of small items. For example, a pair of wall transformers marked 25W and a toy lamp rated 17W. What's my current per watt at 125VAC?

The single-pole configuration would be

mains

while the double-pole would be

mains

Is there any reason to prefer one over the other? Is one more likely to arc than the other?

Thanks PSM

Agreed. Bringing X10 into the picture was a complexity and expense I wanted to avoid. A hard CMOS line is protocol-free, isn't as susceptible to radio interference (intentional or accidental), and would cost well under $10 to implement. As for safety, I'm not ignorant to any electrical and/or fire hazards inherent in this mod. The whole reason this idea seems reasonable is that outlet strips already have a big power switch, so what's the harm in inlining and/or replacing that switch with a relay of the same contact rating? Nothing significant, as long as I'm not careless.

Thanks PSM

I'm only calling them "transformers" because "AC-to-DC adapter" is a bit long-winded and I've never been partial to the term "wall wart". But, in any case, that's what I'm talking about--black boxes with transformers, bridge rectifiers, and probably a couple of other things (never actually broken one open).

What general rules are to be applied when determining whether a load is resistive or inductive? Having no formal training in such details, I tend to assume that something with a coil in it is inductive. By this logic, the AC-DC "transformer" (itself loaded with a small electronic device such as a router, cable modem, laptop, ...) is inductive, the motor part of the toy lamp is inductive, and the incandescent bulb part of the lamp is resistive. I get the feeling that I'm entirely off on at least one of these.

That is not only what I meant but in fact what I thought I had said (abbreviated to a single "out" socket). My prediction of ambiguity in my illustrations leaves something to be desired...

Thanks PSM