# Tag Info

46

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 ...

43

Tying the wiper and one end pole together effectively turns the potentiometer into a simple variable resistor (or "rheostat"). It no longer functions as a voltage divider would, but it does mean that in the case of a failure of the wiper contact (intermittent contact with the carbon track), you'll still have a known maximum resistance value, instead of ...

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 ...

31

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 ...

27

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

23

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 ...

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.

17

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

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 ...

16

Loctite is often used. However there are many types. In general you hear people talk about blue, green and red (242, 290, and 271). Blue prevents inadvertent movement due to vibration and such. With moderate force the pot could be turned. Green is stronger, usually you need to apply a little heat before it can be turned. Red requires a lot of heat and would ...

16

Now that you have provided more information, a voltage regulator is not actually what you want. I will go ahead and leave that part of the answer in here for reference though. What you actually want is a voltage divider. A voltage divider looks like so: and follows the formula of . Selecting Values for your System Note, Majenko already answered with a ...

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

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 ...

15

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 ...

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

MAKING YOUR OWN VARIABLE RESISTORS Anything conductive, accessible, doesn't oxidise, able to be "wiped" with a wiper (resistor pickup) with adequate dying "too quickly". As this is as much for fun as anything else "too quickly" may be able to be of lower duration in time or cycles than usually. Resistance values that you generate may be lower than not, ...

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

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 ...

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

Yes, you can. David isn't wrong that if you just had one variable resistance in series with the resistor, adjusting it wouldn't seem very linear in relation to perceived brightness. But if you introduce some resistors in parallel, the picture changes: I tested these values with a red LED and it works pretty great. You could do all the math, but really it's ...

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.

11

They let the 555 generate the clock pulses for the Johnson counter (the 4017). It's a typical AMV (Astable MultiVibrator) setup. The capacitor gets charged through both resistors until 2/3 Vcc is reached (internal comparator level). This sets a flip-flop which activates the Discharge output (DIS). Through DIS and the potentiometer, the capacitor is ...

11

Incremental encoders often have a haptic detent, and most have a push-button built-in. The detent momentum to overcome the detents may vary from hardly feelable to a clear click. There are also encoders which run smoothly, without detents. Most encoders have between 12 and 30 detents (and also pulses) per revolution.

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