Volume pot

[cyberman9000]

Does a 50 ohm volume pot have a constant impedance of 50 ohm's or does it vary from depending on position of wiper? Would it vary from maximum resistance of 50 ohm's(no sound)to minimum amount of resistance (loudest setting)?

Thanks you!

[Klipschguy]

Impedance does vary with the postion of the wiper. Volume controls are basically variable resisters where the resistance varies with the position of the wiper. There are basically two types of volume controls.

1) linear taper where the resistence varies in a 1 to 1 linear relationship to the wiper position i.e. 1/4 volume = 1/4 resistance, 1/2 volume = 1/2 resistance, or some other linear type relationship.

2) the other type is an "audio taper" where the resistence is logarithmic relative to the postion of the volume control. If volume verses resistence where plotted on a graph for the linear type, the line would be a straight slope, whereas the log taper (audio) would be a curved slope.

Audio taper pots are usually used in audio equipment.

Also, I am not an expert in this area, so any electrical engineers out there please feel free to clarify or correct any of the above information.

One other thing, I think in some tube equipment the volume control varies the voltage of the grid bias to control the flow of electrons like a valve to the output tubes, but I'm getting out of my league here.

Klipschguy

[Weiming]

Hi,

A 50ohm volume pot varies from 0 to 50ohm I think. But I have never seen a 50ohm pot before. I have seen 50k, 75k, 100k.

The way it works is that at 0 ohm, the volume will be the softest while at 50 ohm, it will be loudest.

Input

/

> (50 ohm, loudest)

< <--- wiper switch

>

< (0 ohm, softest)

/

Ground

Weiming.