How to Wire a Rheostat
You may need to wire a rheostat for your audio electronics projects, like stereo volume control and amplifiers. It's a straight-forward process, just apply the proper soldering technique used to wire rheostats to circuit boards and control boxes. Match the rheostat wiring to the appropriate terminals, and run the wire leads to other components (such as audio inputs and outputs on your stereo system or sound amplifier) for controlling volume. And be sure to calibrate a rheostat volume control to accurately measure changes in volume.
Things You'll Need
- Soldering ironSolder RheostatCopper wireWire cutters
Implement a Rheostat for Audio Electronics
Unscrew the nut, counter-clockwise, from the threaded collar. Then slide the nut off of the shaft. Remove the washer by sliding it up, and then take it off of the shaft as well.
Place the rheostat on your mounting board (PCB, plastic box or other circuitry).
Slide the washer onto the shaft.
Place the nut back on to the shaft. Turn the nut clockwise until the nut and the washer are pressed tightly against the PCB, plastic box, or whatever circuitry you are implementing your rheostat into.
Wire all three terminals on the wafer. (The terminals are metallic arms with a circular end protruding over the edge of the wafer). Start by placing a copper wire through the thread (hole in the terminal), and bend it slightly. Touch your solder with your soldering iron, and stick the solder onto the copper wire. The solder will cool quickly, bonding the copper wire to the metal terminal. Click off the excess solder with a pair of wire cutters. Solder a wire for each terminal.
Take the lead wire from terminal number 1 (the terminal on the left side of the wafer), and connect it to the ground wire. The ground wire is marked "GND" on audio circuit boards. Attach the center lead wire to your "Line Out." Connect the third terminal (the wire on the right side of the wafer) to the "Line In." This is the most common way to wire a rheostat (especially in the popular audio devices). To convert the rheostat into a volume control, wire a resistor to the second lead wire on the rheostat, and connect the other end of the resistor wire to the ground wire.
Turn the shaft all the way to the left, counter-clockwise. This sets the rheostat to zero on the numeric dial (for volume control and other dial controls).
Place the knob on top of the rheostat's shaft.
Loosen the screw on the side of the rheostat's knob just enough to allow the knob to slide comfortably on to the shaft.
Hold the knob still so that the pointer (a white mark on the knob) is aligned with the zero on the volume calibrations. Tighten the screw in the knob with a screwdriver.
Test the calibration by turning the dial all the way to the right, and then back to zero. If the white mark on the knob is perfectly aligned with the zero on the volume control (or other audio control), then you're done. If not, you need to loosen the screw on the knob, and then realign the knob again.