Straight talk about potentiometers

[duffman]

Well, I am a bit confused about potentiometers. I was wondering if someone could help me out. on schematics they show up as the two on the left.
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But this is what a pot looks like.
so what goes where?
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Also I have seen pots with two rows of 5 legs. What the @#%@# is that?!
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I also have a questoin abou resistors that look like the diagragm all the way on the right of my first pic. what are resistors liek that?! [/img]

 

[bmcculla]

The first drawing is just a standard symbol for a Pot - the two legs and a wiper. As the Wiper moves the resistance between on leg and the wiper decreaces and the resistance between the wiper and the other leg decreaces. The Center drawing is a standard pot set up to be a variable resistor. The reason the wiper is connected to one of the legs is to set the fail state. This connection eleminates the resistance of the lower part of the pot resistor causing the whole thing to give the resistance of the top part. The fail state, if the wiper fails and disconneccts from the resistor, can be set either to a short or full resistance instead of a floating undefined condition without this type of connection.

The last drawing I havent seen before but it looks like a resistor with a bunch of taps. Like a pot but each tap is evenly spaced giving equal resistance between each step.

The pot with 10 legs is a bit strange It might be a digital encoder instead of a pot. A little testing with your multimeter should help figure our what each pin is doing.

Brent

 

[ChrisP]

What markings, if any, are on the 10-pin device?

 

[zevon8]

what you have there is a log-pot used for volume control, with a extra tap connection for a "loudness" control. quite common in audio gear.

the extra tap is fixed at a given percentage of the pots range, and is used for a boost circuit that is usually controlled by a switch.

log pot means a pot with a logarithmic taper to its resistance element. this gives a non-linear output from the pot, something needed for audio amps, since you require a "doubling" of the output to sense a change in the perceived volume. the resistance will slowly start to rise, then quickly ramp up to its maximum level.

here is a link with some more info:

https://www.angelfire.com/electronic/funwithtubes/Amp-Volume.html

 

[Johnson777717]

Maybe this will help?

 

[panic mode]

it would really be best if you simply take multimeter
and try it out. you can only learn, nothing will be damaged.