59

If you do this, then it will waste a lot of power: simulate this circuit – Schematic created using CircuitLab You'll also need a very large and heavy potentiometer because it will have to handle all the power that the speaker can handle. If you do this, then almost no power will be wasted: simulate this circuit The signal is very low power, and you ...


50

With the newly added original schematic, we can see that this is a RC oscillator circuit. To achieve your real goal of adding a half tempo switch, we can divide the tempo in half by adding a second capacitor with the same value as the original one. With the switch the resulting circuit segment would look like this: simulate this circuit – Schematic ...


40

How to get the most out of a potentiometer? In many precision, low-noise designs, it's a bad idea to start with to even have the signal routed through the front panel. So, at the very least, the control element should merely produce a voltage signal that governs a voltage-controlled amplifier/attenuator. With a potentiometric source, you can buffer and low-...


34

That's a rotary encoder - not a potentiometer. The encoder pulses are sent to the microcontroller which adjusts the volume of the system. Figure 1. 2-bit rotary encoder waveforms. The relative phase of the signals indicates clockwise/anti-clockwise rotation and can be used by the controller to count up or down. Links: How does a Rotary Encoder work ...


32

The device Spehro Pefhany's answer builds out of two pots is actually available as a single unit, for example the ALPS RDC803101A. If you turn it, you get two sawtooth signals that are 180° out of phase, so when one output is in its “dead zone”, you can use the other one instead to determine the position. This model also has no detents, so no clickyness at ...


28

If you connect to the top and wiper, you can use the potentiometer as a simple variable resistor. If you connect to the top and wiper, AND short wiper to bottom, you are still using it as a variable resistor, but with one important difference : if the wiper goes open circuit, the resistance value is 10K rather than infinity. That can: reduce crackling ...


27

It stops the resistance from going to infinity if there is dirt on the potentiometer track. (it just goes to max instead)


25

Consider this: - Sound level is measured in dB and, a 10 dB increase/decrease in signal equates to a doubling/halving of loudness as perceived by the ear/brain. Look at the picture above and ask yourself which is the better choice for smooth (coupled with extensive) volume controller. Below are the Fletcher Munson curves showing the full range of decibels ...


24

This is better.. simulate this circuit – Schematic created using CircuitLab Advantages are: Low sensitivity to pot tolerance and tempco (you can use precision resistors for R2/R3) Quite linear and almost constant fine adjustment range in mV Quite constant (+/-0.5%) and predictable output impedance (minimum 9.09K maximum 9.195) Low sensitivity ...


23

The "A" part stands for audio taper. "B" would be linear taper and "C" is a reverse audio taper: - Image from this website What taper means in this context: - Audio Taper Potentiometers are log taper potentiometers that are specifically designed for use in audio applications. Audio taper potentiometers are the potentiometers ...


20

First, to address the name issue- in ancient times there was an instrument called a potentiometer. I (being somewhat 'experienced' myself) have actually used them for serious work such as calibration of hundreds of control instruments, though they probably mostly can be found in museums now. It was used to measure (meter) voltage (potential) using a voltage ...


20

The datasheet has a pretty thorough description of the use of the ADJ pin with \$R_1\$ and \$R_2\$: Since both \$R_1\$ and \$R_2\$ appear in the equation for the output voltage $$V_{\text{out}} = 1.25\text{ V} \times \left(1 + \frac{R_2}{R_1}\right) + I_{\text{ADJ}}R_2$$ you need both in order to realize an arbitrary output voltage. Depending on your ...


19

The clicks are called Detents. You are looking for encoders with 0 detent points, the Alps EC12E2430404 is one example.


18

You drill a second, much smaller hole. That protrusion keeps the pot in place when it gets turned past one of its ends and the screw isn't enough to hold it tight.


17

What does it mean that the human ear isn't linear? In this context, if the human ear were linear, a sound wave with twice the power of another would sound twice as loud. However, the fact is that a sound wave must have 10 times the power of another to sound twice as loud. How does the log changes in the pot resistence relates to sound waves and how ...


17

Some pots are built on ceramic substrates, with highly conductive strips at either end: The wiper may have some travel over the highly-conductive (silver-coloured part) for some degrees before it starts wiping the resistive section (grey-coloured part).


17

Overview I'll avoid depending upon algebra as an explanation. (Because algebra, while providing quantitative answers, doesn't often help people understand something unless they are very fluent with mathematics.) Regardless, it's still helpful to have the datasheet available. So here is TI's LM317 datasheet just to make it convenient when needed. The best way ...


16

The best continuous rotation sensor I've used is the AMS series. Something like this might suit your purpose. Of coursed they can't support infinite output values, but associated with an MCU you can set it to mid scale each time you turn your unit on, or remember last settings. There are also plenty of relatively cheap optical encoders that would allow ...


15

The name for the thing you're looking for is rotary encoder. In particular, the incremental rotary encoder. If connected correctly, you will get pulses such as these: Depending on the direction you're turning, those two pins will flip its state in a different order, so you can find out the direction. Most of the ones that you want to pay for will have up ...


14

To search for the described part, use the keywords potentiometer with detents. The specifics mentioned would suggest a potentiometer with 10 detents, such as this one on Amazon, or another on Jameco. The detents can be low torque (a gentle click at each transition) or high torque (a firm click). The common / inexpensive ones are low-torque, but they seem ...


14

I have not seen something like that, does not mean that it does not exist. It does not particularly lend itself to construction with normal pot designs, including modular ganged pots, because the leads usually come out of one side. There are pots without end stops, however they have a dead angle. Expensive long-life ones are called 'servo pots'. You ...


13

A ganged potentiometer is two or more variable resistors of the same or sometimes different value, ganged together on one adjusting shaft, normally used on stereo systems as a volume control so that one can vary the volume of both channels at the same time. They are commercially available with from two to four sections. Ganged pots are also used for tone ...


13

Loudness control From Elliott Sound Products Beginner's Guide to Potentiometers: Ah! Another one ... Most pot 'gangs' are 3 terminal types, but there are some with a tapping partway along the resistance element. This was used in the bad old days to create a 'loudness' control, where the bass and treble are increased at low levels to compensate for the ...


13

It is very unlikely that your system is configured as shown in your schematic. With the leftmost active pot wiper fully left you short out the voltage reference. simulate this circuit – Schematic created using CircuitLab Figure 1. (a) A more likely arrangement in your rhythm box. (b) Dividing the output by two. (c) Dividing the input by two. (a) ...


12

Although this question has been answered I just wanted to add something for those seeking an ideal logarithmic potentiometer law for simulation. A mapping from linear law to logarithmic law can be found in the general form: $$ y = a\ b^{x} + c$$ Let this equation function define a mapping from \$0\leq x\leq1\$ to \$0 \leq y \leq 1\$, where \$a\$, \$b\$ and ...


12

It's a rotary encoder, rather than a potentiometer. It looks like this may be your part, but you may need to contact them to get a datasheet.


12

The resolution or adjustability is a result of the pot geometry, dimensions element materials and construction and wiper design, the number of turns is not directly related - for example a trimpot with 20+ turns may have no better resolution or adjustability than a single-turn trimpot with similar electrical element length. Wirewound pots have a resolution ...


11

Andy has answered this, and he hinted at the end that A-taper (log) pots are not perfect. Here is a comparison between an ideal log response and what a real commercial log pot actually does (taken from here): It's a two-segment piecewise linear approximation to the ideal log taper (dashed line). Crude, but it does the job well enough in many cases. Note ...


11

A Varistor is a voltage-dependent-resistor. Its resistance depends on the voltage applied to it, and it is a 2-terminal device. or A Potentiometer is a fixed resistance with a mechanically adjustable wiper which can be moved from one end of the fixed resistance to the other, forming an adjustable voltage divider. It is a 3-terminal device. or A ...


Only top voted, non community-wiki answers of a minimum length are eligible