What is variable resistance box?
Variable resistor. A resistor box, offering fixed resistance values between 100 Ohms and 470,000 Ohms. The scale is logarithmic, with the resistance increasing by a factor of ten with every three steps.
Where does a variable resistor go in a circuit?
Variable resistors are mostly used where voltage control and current limiting is needed. In applications where voltage control is needed, the potentiometers are preferred as their connection suits for the same.
How does a resistor box work?
In resistance box, the resistor is fixed inside the box. They are arranged in such a manner that the value of resistance varies at every step. The box consists the rotary selector switch. The variable resistances are obtained by rotating the selector switches.
Why would you use a variable resistor in an electrical circuit?
Variable resistors are widely used in electric circuits to adjust the value of current or voltage, since the resistance of variable resistors can be set to a certain value. Variable resistors allow you to adjust the value of voltage by changing the resistance and keeping current constant .
Why do variable resistors have 3 pins?
A 3 terminal pot used with 3 terminals, is basically just a voltage divider. As you move the wiper, you increase one resistor in the voltage divider, while decreasing the resistance in the other. So a 3 terminal pot is a variable voltage divider.
Which wire is used in resistance box?
Types. Nichrome, a non-magnetic 80/20 alloy of nickel and chromium, is the most common resistance wire for heating purposes because it has a high resistivity and resistance to oxidation at high temperatures. When used as a heating element, resistance wire is usually wound into coils.
What is the main application of the resistance box?
Features of Resistance box The main application of the resistance box is to control the specific value of current to flow through the circuit. The construction of the box is simple and cheap. The resistance box is available in different designs. It is used for testing and designing the circuit in the laboratory.
How do you connect variable resistance?
When used as a variable resistor, connections are made to only one end of the resistive track (either pin 1 or pin 3) and the wiper (pin 2) as shown. The position of the wiper is used to vary or change the amount of effective resistance connected between itself, the movable contact, and the stationary fixed end.
Does resistance box have positive and negative terminal?
The simple resistance box has two copper terminals for connecting the positive and negative terminal of the circuit.
Does variable resistor affect voltage?
Variable resistors allow you to adjust the value of voltage by changing the resistance and keeping current constant .
What is the purpose of variable resistor?