Potentiometer: what it is, what it measures and where it is applied?
Potentiometer - what is it? In short, this question can be answered by the fact that the device is a device that performs the function of a current regulator. In addition, the device has rheostat options. Potentiometer in demand in the electronics industry, equipped with resistors with tap contacts. Modifications can vary in the number of operating cycles, the main purpose - the elements of computing devices, volume controls, the adjustment of fuel supply to the engine. Consider more information about them.
Let's try to figure out - potentiometer, what is it in general? A typical device circuitry includes a resistor, contacts, and taps. Some models are equipped with diodes, keys for different variations have a difference in conductivity. Typically, the design uses passive type resistors, and a pair of contacts is located in the lower compartment of the case.
Other models are distinguished by rheostat keys with movable contacts, which have a high conductivity. The bandwidth of the charge depends on the cutoff frequency, an average of 2 thousand KHz. In addition, variations are produced with the power of two polarities, they are used exclusively in computing devices. Calibration of the device is carried out on bridge circuits, the connection is carried out through a couple of special conclusions. The spread of resistance at a minimum of 2 percent, the negative voltage reaches a rate of 3.5 volts. The cost of devices varies in the range of 300-600 rubles.
We continue to study the potentiometer. What is it in mechanical performance, consider next. The device is a current regulator equipped with a rotary type controller. The keys are of resistive type, there are two terminals, the through resistance withstands up to 3.5 Ohms. The limiting linear distortion is 90 dB, the maximum negative voltage is 3.5 V.
It should be noted some features of this type of devices, namely:
- Type of resistors - open.
- Rheostatic mode - mostly absent.
- Allowable positive voltage - 2.4 volts.
- Marking of enclosures - РР-20 or Т23.
- The average cutoff frequency is 2400 kHz.
The mechanical model is great for reverse control, and the bandwidth depends on the key parameters.
The electronic potentiometer of the valve has a reversible type, it is often used as a volume control. The device is mainly equipped with two keys, supports about ten cycles, there is an option of software selection.
The considered devices often become elements of computing devices. The cutoff frequency limit is about 3,000 kHz. Many parameters depend on the design features and manufacturer. Linear distortion is about 80 dB, key skip is 3.5 microns. To adjust the gain of these devices are not intended.
More precisely, the potentiometer, what it is, will help review some models of the device. To begin, consider the modification of Skal. In this series, the most popular models under the index 103, 105, 107.
Brief description of devices:
- Skal 103 - a device designed to adjust the resistance in the circuit with alternating current. This device features contacts of exclusively mobile type. There is one key, a passive resistor located near the terminals. A software sampling function is provided; there is no rheostat mode. The housing marking is P20; the potentiometer is adjusted in levels.
- Model 105 is an automatic device used in systems with alternating current. A passive type resistor is installed, the key is located near the terminals. The modification is optimal for computers, because it has a high cutoff frequency, the linear distortion parameter is 56 dB.
- Option 107. This device has a level frequency of 2400 kHz, resistive key, passive resistors located in the lower compartment of the case. Its marking is PP21, the lowering band at the maximum is 2.3 microns, there is a rheostat mode.
The device of this brand under the index 1200 is connected via a pair of pins. The potentiometer sensor can withstand four cycles with a cut-off frequency up to 2300 kHz. The modification is suitable for adjusting the sound and timbre of guitars, and is also used as an element of computing technology.
EP-3000 has a small spread of resistance. The key of the rheostatic type is located near the terminals, the case has a special protection. There is an option of software sampling, calibration is performed by bridge circuits, one resistor is provided. The version is not suitable for filter settings and gain control.
The modification of EP-2110 is used for digital reverse control. There is a rheostat key, a pair of pins in the lower part of the body, software sampling. Setup is done automatically without the participation of bridge circuits.
How does the motor potentiometer?
Often, the owners of modern cars are trying to squeeze the maximum power out of the car, pushing the accelerator pedal all the way. This decision is not successful, because the aggregation between the power unit and the gas pedal occurs through a special throttle sensor (potentiometer). "Mercedes", "BMW", "Volkswagen" and most other cars equipped with such a device.
The device is designed to adjust the fuel supply to the engine in metered portions. In addition, the device monitors the dynamics of pressure on the accelerator pedal and determines the number of revolutions at idle.The constituent elements of the potentiometer for a car are two resistors, one of which is of a stable type, the second is a variable analogue. The total resistance of the elements is 8 kΩ.
Principle of operation
The operation of the potentiometer is that one of the terminals is supplied with a voltage of 5 volts, while the other edge must be grounded. The middle pin is connected to a special controller that provides the necessary information on the throttle. With the valve completely closed, the voltage does not exceed 0.7 V, and in the open position it reaches 4 V.
A potentiometer sensor is attached to the body of the flap by means of screw fixation. The device interacts with the axis of rotation using a special hole in the indicator socket. To properly configure the device, you must connect the sensor connectors, activate the ignition, measure the input voltage. This indicator should not exceed 0.7 volts. If the reading is too high, adjust the indicator mount with screws to normal. If there are doubts about which potentiometer to pick up, it is advisable to contact a specialist or service center.