You will need
- The execution of these works will require a basic knowledge of radio engineering,the techniques of measuring instrument (tester, ohmmeter), as well as skill with a screwdriver, soldering iron, pliers.
Determine with technical documentation or schematics, what is the function of variable resistor in the device (adjustable resistance or potentiometer). Install using the specification or calculation method of the nominal value/value of the variable resistance and type. Then select the proper type and the value of variable resistoror its equivalent.
Test it using the meter measuring resistance (ohmmeter) find the output, which changes the resistance. It is called "slider".
Produce switching of the contacts, a variable resistorbut in accordance with her function: connect the contact of the slider a resistorand one of the two remaining findings to obtain the variable resistorand or use all the conclusions of the resistorand to use it as a potentiometer.
Install the device in the device or on mounting plate and connect it conclusions in accordance with the concept. Check that the values of the fuse links (fuses), and enable compliance with safety standards the device to check its efficiency.
Advice 2: How to connect the resistor
There are different wiring diagrams depending on which variable resistor can be as a source of variable resistance and potentiometer. All depends on the type of connection of the third output.
Examine carefully the scheme or documentation to determine how to connect the resistor in this particular case. As mentioned earlier, it can perform two functions: a source of variable resistance and the potentiometer. The documentation should be provided a variable resistance in the connection. It is best to determine the number of thumb, using a special measuring device. So you will be able to more accurately pick up a variable resistor or some equivalent.
Take an ohmmeter to measure total resistance in the circuit. Connect the terminal on the closing contacts. The resistance value should be reflected on the screen. Then measure the resistance at a particular node schema. If no value is reflected, then a connection somewhere is broken.
Carefully inspect all contacts. If needed, connect them to any metallic wire. More reliable connection you provide when you soldering the resistor. Depending on the received values, choose a suitable resistor. Proceed to its installation in the scheme.
Wipaire old broken-down resistor. Try to make the solder residue does not fall to the circuit to avoid circuit of neighboring contacts. Then take a new resistor of variable resistance. Solder it just like you just extracted.
Follow the same precautions to prevent the formation of bridges between contacts. Turn on the circuit, check its efficiency. If it does not work or works incorrectly, peredayte resistor. Some resistorAh foreign-made contacts can be a little different. Swap the center pin with either of the extreme. If it did not bring the expected results, check the device for faulty new resistor.
Variable resistors are used in devices where it is necessary to vary the value of resistance. With the change in resistance in the circuit will vary the current in accordance with Ohm's law. And the output of the potentiometer, we can obtain any value of voltage, but it will be always not more than the input voltage. Potentiometers are used to adjust device parameters such as output voltage, power, volume, etc.