If i have a potentiometer that all of the range of adjustment occurs briefly within the full range. What does that indicate? Thanks in advance.

 

Either it's broken or it's an audio taper potentiometer.

 

If i have a potentiometer that all of the range of adjustment occurs briefly within the full range. What does that indicate? Thanks in advance.

The restive material may be burned out.

 

Either it's broken or it's an audio taper potentiometer.

I'm with #12.

If you are in the UK the audio taper potentiometer maybe more commonly know as logarithmic.

 

And just for s&g, I agree as well. It's likely an audio pot.

 

If i have a potentiometer that all of the range of adjustment occurs briefly within the full range. What does that indicate? Thanks in advance.

Assuming nothing's broken, it could mean many things.

Can you post a schematic of your circuit, please, and include the pot's part number?

 

Can you measure the resistance from one end to the wiper for various wiper positions?

 

Potentiometer taper

My guess based on your limited description would be an audio taper potentiometer. Read the link to understand why it seems non-linear in nature.

Ron

 

I think I found a schematic. The part number will have to be provided by the Thread Starter.

 

Is this pot already in a circuit that was fine and is just now behaving this way, or is this a new use for the pot? If the latter, what is the application, and what is the pot supposed to do in the circuit?

ak

 

Ok sorry it took a minute to respond. I'm at work still pondering this. Hooked up last night thru lm317 power supply. Wanna say 13.6 v into the lm317. Oddly only getting 7.6v out with said pot. I added another lm317, 10v. Added a total of four in parallel. 12.4 v. Pot never did act right I have no more good ones. When I tested resistance. Seemed to spread across the normal range. With voltage - all changes within a small window.

 

Only things I know about the pot are that it's 20k and was pulled from a vaporizer.

 

Ok sorry it took a minute to respond. I'm at work still pondering this. Hooked up last night thru lm317 power supply. Wanna say 13.6 v into the lm317. Oddly only getting 7.6v out with said pot. I added another lm317, 10v. Added a total of four in parallel. 12.4 v. Pot never did act right I have no more good ones. When I tested resistance. Seemed to spread across the normal range. With voltage - all changes within a small window.

All that verbiage is nonsensical and smacks of trolling.

If you can't / won't post a schematic, why should we (me , anyway) bother with you?

 

WTF? You don't know how to wire an lm317 plz don't!

 

WTF? You don't know how to wire an lm317 plz don't!

No, junior, listen up. *We* know a lot of things about the LM317. Obviously you don't, or you wouldn't be asking us.

Also, note that your first post didn't mention the 317 or any other component, active or passive. There are literally hundreds of ways to interconnect four LM317's. Reread your post #11. Do you honestly think that it conveys as much information as a schematic involving 4 integrated circuits plus a completely unknown number of other components?

Here's a clue: There is no simple way to direct-connect IC voltage regulators in parallel. None of them. Ever.

Three step plan for web forum success: Think; think again; write.

ak

 

Again a very simple question. If your not smart enough to answer it don't. Petty ugliness just looks bad on you.

 

So easy at this point I think I'll just answer it for myself. Unless it's the pot. It's the circuit and no it should never act that way unless it's that one pot mentioned for audio. Heck even I feel embarrassed. So you definitely should.

 

What is the value of the other resistor?

If your circuit is configured as on the datasheet, then a 20K pot gives an adjustment range of 1.25 V to over 106 V. With a 13.6 V input. it doesn't matter what taper characteristic the pot is; it is way too large a value to give you a decent adjustment range.

Separate from that, strange things will happen when the regulator runs out of headroom. You don't say what your load current is, but the minimum Vin to Vout dropout voltage is between 1.5 and 2.5 V depending on circuit conditions. Getting a regulated 12 V output from a 13.6 V input is possible only at very low load currents.

You did not say who made your chips, but the National datasheet has an internal schematic of the 317. From this you can see why a direct parallel connection of multiple regulators can not work.

ak

 

analog you ok man? i have 4 running in parallel. the question has been adequately answered. have a nice day.

 

analog you ok man? i have 4 running in parallel. the question has been adequately answered. have a nice day.

Obviously with little idea of what you are doing and arrogant. Bad combination.