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.
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.
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.
Advice 3: Why the need for a resistor
People who start to understand electric circuits and electronic devices have to deal with many elements that literally stuffed the circuit Board. One of the most common parts used in electronics, resistor. It is designed to perform several important functions and often cannot be replaced by other circuit elements.
What is a resistor
The term "resistor" is derived from the English verb resist, which means "to fight", "oppose", "resist". In a literal translation on Russian language the name of this instrument means "resistance". The fact that in electrical circuits, current flows, which is experiencing internal resistance. Its value is determined by the properties of a conductor and many other external factors.
This characteristic current is measured in ohms and is connected with the dependence of current strength and voltage. Conductor resistance equals 1 Ohm, if it is leaking current to 1 ampere, and to the ends of the conductor is applied a voltage of 1 volt. Thus, using artificially created and introduced into the electrical circuit of the resistance can be adjusted and other important system settings, which can be calculated in advance.
The scope of the resistors is extremely wide, they are among the most common elements of the installation. The main function of resistor is to limit current and control. It is also often used in circuits division voltage when it is required to reduce this characteristic of the circuit. Being a passive electrical elements, resistors are characterized not only by the value of nominal resistance, but also power, which shows how much power the resistor can dissipate without overheating.
What are resistors
In electronic devices and household electrical systems use multiple resistors of different shapes and sizes. Different from each other, these miniature devices are not only in appearance but also in value and performance. All resistors are divided into three groups: fixed, variable, and trim.
Most often the devices can meet the constant resistors of the type, reminiscent in appearance of elongated "barrels" with the conclusions at the end. The resistance parameters in devices of this kind essentially do not vary from external influences. Small deviations from the nominal value can be caused by internal noise, changes in temperature or the influence of power surges.
Variable resistors allow the user to arbitrarily change the resistance value. For this purpose the device is equipped with a special arm having a slider or rotatable. The most common representative of this family of resistors you can see in the volume controls, which are fitted in the audio. The rotation arm is able to smoothly change the parameters of the circuit and, accordingly, to raise or lower the volume. But the trimmer is designed only for relatively rare adjustments, so have a pen and a screw with a screwdriver.