# What is a resistor and what does it do?

A resistor is a passive two-terminal electrical component that implements electrical resistance as a circuit element. In electronic circuits, resistors are used to reduce current flow, adjust signal levels, to divide voltages, bias active elements, and terminate transmission lines, among other uses.
A.

### Why do we use resistor?

Resistance is the measure of opposition to electric current. A short circuit is an electric circuit offering little or no resistance to the flow of electrons. Short circuits are dangerous with high voltage power sources because the high currents encountered can cause large amounts of heat energy to be released.
• #### How does the resistance affect the voltage?

Non-linear resistance, does not obey Ohm's Law but has a voltage drop across it that is proportional to some power of the current. Resistance is pure and is not affected by frequency with the AC impedance of a resistance being equal to its DC resistance and as a result can not be negative.
• #### Is current affected by resistors?

Ohm's law relates the voltage across and current through a resistor. In general, a change in resistance will change both the voltage across and current through the resistor. For example, consider the simple voltage divider circuit - a voltage source and two resistors , , connected in series.
• #### What is the function of a diode?

The most common function of a diode is to allow an electric current to pass in one direction (called the diode's forward direction), while blocking current in the opposite direction (the reverse direction). Thus, the diode can be viewed as an electronic version of a check valve.
B.

### How does a resistor work?

Devices called resistors let us introduce precisely controlled amounts of resistance into electrical circuits. Photo: Four typical resistors sitting side by side in an electronic circuit. A resistor works by converting electrical energy into heat, which is dissipated into the air.
• #### Do resistors have a polarity?

If I understand your question, then yes - resistors are reversible, in the sense that they can be connected to the circuit in either direction. Resistors are not like diodes or capacitors. They do not have a polarity. The conduct (or resist) current equally in both directions of current flow.
• #### What is the use of a variable resistor?

Simply put, a variable resistor is able to have its electrical resistance adjusted. These devices are used when working with electrical circuitry because they help to control voltage and/or currents. They specifically work with voltage and currents that are a part of the circuit.
• #### Who invented the resistor and when?

Otis Frank Boykin

Updated: 16th October 2019