Sorry about the terse unreadable title. Had to do it to circumvent the acknowledged forum bug.
I'm following plans for an electro-etcher/marker, found in multiple places online. Such a device uses DC current to etch and AC current to mark. Various effects on the etching process can be achieved by controlling the voltage and current of the circuit. The basic design is to put 120V wall AC through a step-down transformer, rectify the output, and not much else. It isn't even particularly important to smooth the DC circuit (the discontinuities in rectified DC apparently have little effect on etching behavior).
To switch the device to an electro-marker you simply bypass the rectifier entirely and work directly off the stepped-down AC.
One thing I would like to verify, although this isn't my main question, is whether it is appropriate to connect the transformer chassis to the "wall" ground (the green ground from the wall, bundled with the 120V AC). Is that the right thing to do?
What I would like to add is a two-volt-option switch. In high mode it use the outer taps of the transformer and in low mode it would use an outer tap and the center tap. That's pretty much it...but I have one question that I cannot for the life of me find a solid answer to. In fact, I find conflicting answers at various resources.
In each of the two configurations, I don't know whether it is optional, required, or prohibited to attach the unused transformer tap to the wall ground (to restate, this is the green ground from the wall, bundled with the 120V AC), or alternatively to leave it floating (right term?). In high-voltage mode, thus not using the center tap, do I leave the center unconnected or do I connect it to wall ground? The followup question, for which I have found practically no information whatsoever, is the low-voltage mode. Do I leave the unused end-tap of the transformer open or connect it to wall ground?
Thanks a bunch!
I'm following plans for an electro-etcher/marker, found in multiple places online. Such a device uses DC current to etch and AC current to mark. Various effects on the etching process can be achieved by controlling the voltage and current of the circuit. The basic design is to put 120V wall AC through a step-down transformer, rectify the output, and not much else. It isn't even particularly important to smooth the DC circuit (the discontinuities in rectified DC apparently have little effect on etching behavior).
To switch the device to an electro-marker you simply bypass the rectifier entirely and work directly off the stepped-down AC.
One thing I would like to verify, although this isn't my main question, is whether it is appropriate to connect the transformer chassis to the "wall" ground (the green ground from the wall, bundled with the 120V AC). Is that the right thing to do?
What I would like to add is a two-volt-option switch. In high mode it use the outer taps of the transformer and in low mode it would use an outer tap and the center tap. That's pretty much it...but I have one question that I cannot for the life of me find a solid answer to. In fact, I find conflicting answers at various resources.
In each of the two configurations, I don't know whether it is optional, required, or prohibited to attach the unused transformer tap to the wall ground (to restate, this is the green ground from the wall, bundled with the 120V AC), or alternatively to leave it floating (right term?). In high-voltage mode, thus not using the center tap, do I leave the center unconnected or do I connect it to wall ground? The followup question, for which I have found practically no information whatsoever, is the low-voltage mode. Do I leave the unused end-tap of the transformer open or connect it to wall ground?
Thanks a bunch!