Popping my post cherry here.
Hello community!
Thank you for the platform, I hope I can understand a lot more about this practice.
I've been working on a very simple project, it's a constant current supply /current limiter, used with a DC 30v adapter, aim to be able to adjust the current from around 5mA to 20mA and hold it there.
Used to connect to two electrodes, it's for electrolysis.
I've followed a diagram, which I will attach.
Made another with a slightly different configuration, but should be the same circuit.
Using LM317LZ, 1kohm 25 turn trimmer pot, and a 49.9 ohm resistor, that's all.
Positive runs through this circuit and then to anode.
Negative power goes direct to the cathode.
..
Buuutt... It's not working like it should, or my reading are just totally off...
To read the current..
I attach.
Ps+ to meter +
Meter - to anode
Ps - to cathode
Switch to 20mA setting on meter and check.. getting far lower current than I should, and the trimmer pot adjustment isn't really doing anything..
Furthermore..
Adjusting the height of the cathode in the solution radically changed the current, which it shouldn't..
Reading current again..
If I attach the (meter negative) to the cathode instead of the anode as I was instructed, I did get a proper reading of a stable current that I could then adjust..
I must have wired something wrong. But I can't figure out how..
I'll attach a pic of my other configuration too..
I don't know what I'm doing wrong. It's such a simple circuit.
..
Some thoughts..
Maybe I'm wiring the trimmer pot in wrong, I have two legs joined together, input and middle, then the other to output. I read about doing that somewhere..
I'm keeping everything right together and mostly just using the legs to connect the components.
Other diagrams have the resistor before the pot, some after, not sure if it matters.
Hello community!
Thank you for the platform, I hope I can understand a lot more about this practice.
I've been working on a very simple project, it's a constant current supply /current limiter, used with a DC 30v adapter, aim to be able to adjust the current from around 5mA to 20mA and hold it there.
Used to connect to two electrodes, it's for electrolysis.
I've followed a diagram, which I will attach.
Made another with a slightly different configuration, but should be the same circuit.
Using LM317LZ, 1kohm 25 turn trimmer pot, and a 49.9 ohm resistor, that's all.
Positive runs through this circuit and then to anode.
Negative power goes direct to the cathode.
..
Buuutt... It's not working like it should, or my reading are just totally off...
To read the current..
I attach.
Ps+ to meter +
Meter - to anode
Ps - to cathode
Switch to 20mA setting on meter and check.. getting far lower current than I should, and the trimmer pot adjustment isn't really doing anything..
Furthermore..
Adjusting the height of the cathode in the solution radically changed the current, which it shouldn't..
Reading current again..
If I attach the (meter negative) to the cathode instead of the anode as I was instructed, I did get a proper reading of a stable current that I could then adjust..
I must have wired something wrong. But I can't figure out how..
I'll attach a pic of my other configuration too..
I don't know what I'm doing wrong. It's such a simple circuit.
..
Some thoughts..
Maybe I'm wiring the trimmer pot in wrong, I have two legs joined together, input and middle, then the other to output. I read about doing that somewhere..
I'm keeping everything right together and mostly just using the legs to connect the components.
Other diagrams have the resistor before the pot, some after, not sure if it matters.
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