The circuits shown here are most certainly not appropriate for general use. I build them for my own enjoyment and curiosity. They usually are dismantled in a few days and the parts are used for something else.

The schematics and designs here are all bench designed using a basic circuit idea and then trial and error to arrive at specific values. They may have problems.

They are connected to a variac with a fuse and current meter. They are turned on and off by slowly turning the variac up and down. They are not subject to any of the rigors of consumer use and they are not intended to be.

I always wear eye protection and turn the power off by turning down the variac. Nothing is subjected to hard switching or a quick turn on. I also work with one hand behind my back if the circuit is to be approached while powered on.

I also continually check to see if the power is truly off as I work on a circuit by verifying the variac is off and the voltmeter and current meter reads zero. It is easy to be interrupted and resume working on a circuit to find that you haven't powered it down so checking continually as one works helps prevent this.

I also power the unit down and let it drain before applying test leads or making any change whatsoever. This part is really a big deal.

If I do post anything that is a working design suitable for general use I'll make a note of it and probably make a big deal of it.