Taper of Potentiometers
On Thursday, 25 January 2018 05:05:17 UTC, rickman wrote:
Phil Allison wrote on 1/23/2018 10:29 PM:
wrote:
------------------------
I have always known pots to either have an audio or a linear taper.
** Tube radios and TVs using carbon track pots used either linear "lin" OR logarithmic "log" taper pots. The log pot would always be for volume.
Log pots had a very gradual rate of increase in resistance as you turned it clockwise.
Audio taper pots arrived with hi-fi amplifiers and gave a quicker rise in volume than a log type, so was preferred by many makers and also guitar amp makers.
The code letters used varied alarmingly, A originally meant linear and C =log. Pots coming from Asia used A = audio taper with B = linear and D = log.
The code letter "E" referred to a "reverse log" pot, useful in instrumentation where the actual gain of a amplification stage must be varied smoothly.
Strangely, I have not come across a reverse linear pot anywhere.
If you give it a thought, you will realize a linear pot is its own reverse.
The reverse doesn't refer to whether the resistance goes up or down, it
refers to which direction the log curve goes, a log taper or an exponential
taper. A linear taper is the same either way... it's linear.
I would very much expect he didn't need to 'give it a thought' to work out something so obvious.
NT
|