Resistors (13)

Resistivity

Ohms Law states that when a voltage (V) source is applied between two points in a circuit, an electrical current (I) will flow between them encouraged by the presence of the potential difference between these two points. The amount of electrical current which flows is restricted ...

Potentiometers

Resistors provide a fixed value of resistance that blocks or resists the flow of electrical current around a circuit, as well as producing a voltage drop in accordance with Ohm's law. Resistors can be manufactured to have either a fixed resistive value in Ohms or as a potentiomet...

Resistor Colour Code Wheel

This handy and simple resistor colour code wheel can be used as a reference for finding the correct resistor colour code of any 4-band or 5-band resistor. Resistor colour codes can sometimes be a little confusing until you understand how they work. But once you get the hang of t...

Varistor Tutorial

Unlike the fuse or circuit breaker which offers over-current protection, the varistor provides over-voltage protection by means of voltage-clamping in a similar way to the zener diode. The word "Varistor" is a combination of the words VARI-able resi-STOR used to describe their m...

Resistor Tutorial Summary

Resistor tutorial summary listing the main points we have learnt through this tutorial section about resistors and resistance. The job of a Resistor is to limit the current flowing through an electrical circuit. Resistance is measured in Ohm's and is given the symbol Ω C...

Resistors in AC Circuits

In the previous tutorials we have looked at resistors, their connections and used Ohm's Law to calculate the voltage, current and power associated with them. In all cases both the voltage and current has been assumed to be of a constant polarity, flow and direction, in other word...

Resistor Power Rating

When an electrical current passes through a resistor due to the presence of a voltage across it, electrical energy is lost by the resistor in the form of heat and the greater this current flow the hotter the resistor will get. This is known as the Resistor Power Rating. Resistor...

Potential Difference

Unlike current which flows around a closed electrical circuit in the form of electrical charge, potential difference does not move or flow it is applied. The unit of potential difference generated between two points is called the Volt and is generally defined as being the potent...

Resistors in Series and Parallel

In the previous tutorials we have learnt how to connect individual resistors together to form either a Series Resistor Network or a Parallel Resistor Network and we used Ohms Law to find the various currents and voltages across each resistor combination. But we can also connect r...

Resistors in Parallel

Unlike the previous series resistor circuit, in a parallel resistor network the circuit current can take more than one path as there are multiple paths for the current. Then resistors in parallel circuits are classed as current dividers. Since there are multiple paths for the su...