Sounds good.Okay, I've got a 10k resistor where the 1k was. Smooth up and down, full range, no spikes, either lightly loaded, or with several amps of load. When I roll thru quickly, it may go high for a few tens of milivolts, but settles back within a second or so.
Sorry, I've searched for it, no luck. It's a "black-box" smps from china, so very little data. I obtained a few for experiments, and to build a quick-n-dirty (well, not too dirty) 10-90v bench supply, as it also features current limiting. It looks like this one:Sorry. I need to see the entire circuit diagram of the power supply.
I need to see where the wiper sits in the control loop. You want to be stabilizing the feedback signal.
Try two pots in parallel worked by the same shaft. i.e. a stereo pot. If one wiper disconnects, the odds are the other one won't. Add a cap as well if you want to. If the impedance of the following circuit is high (i.e. the non-inverting input of an op-amp) then the voltage will not change if only one wiper connects to the track instead of two.if you use a high quality pot there is always the chance that it will become defective and then your nice regulator will put out 20 volts when you have it set to just 5 volts.
It does, but there is a finite number of turns of wire, and that means only a finite number of wiper positions. It's like a multi-position switch (but with an awful lot of positions). The wiper of a potentiometer with a carbon track can take ANY position on the track.I do believe 10 turns refers to shaft rotations not the number of windings.
That's ok - perhaps I didn't make it clear enough which "turns" I was referring to.Yea, I guess I deleted a little too late...sorry
After thinking about it, I figured you already knew that.
That would work in designs that only depend on a voltage signal adjustment. For those that depend on a resistance adjustment the loss of one pot would cause the resistance to go up by 2 times which would cause the voltage to either go way up or way down.Try two pots in parallel worked by the same shaft. i.e. a stereo pot. If one wiper disconnects, the odds are the other one won't. Add a cap as well if you want to. If the impedance of the following circuit is high (i.e. the non-inverting input of an op-amp) then the voltage will not change if only one wiper connects to the track instead of two.
ALso, a stereo pot is much more stable on a pcb than a mono pot unless the mono pot has a bracket.
True. The potentiometer has to be acting as a potentiometer not a rheostat.That would work in designs that only depend on a voltage signal adjustment. For those that depend on a resistance adjustment the loss of one pot would cause the resistance to go up by 2 times which would cause the voltage to either go way up or way down.
Still, for the voltage adjust mechanism i think it would work.
Every-time I pick up the iron, I'm entering a door to a puzzle/maze that has multiple outcomes... How fun!...
If you can accept a control that is ever-so-slightly square-law, then a resistor between wiper(s) and ground will send the output to zero if both wipers lose contact with their tracks - like when you accidentally drag the power supply off the bench by its cable and it lands on the pot.
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