Conductance

The reciprocal of resistance (R) is conductance (G), which is measured in siemans (S). Hence: Worked Example 1 Find the conductance of a conductor of resistance 27 Ω. Show / hide answer G = 1 / R = 1 / 27   = 0.037 S = 37 mS Worked Example 2 Find the...

Magnetomotive Force

Magnetomotive Force (MMF) performs a similar role in a magnetic circuit to the electromotive force (EMF) of a battery in a basic electrical circuit, thus acting as the ‘prime mover’ of an electromagnetic system. The MMF resulting from passing an electrical...

Circuit Theorems

Ohm’s Law Kirchhoff’s Laws Maximum Power Transfer Theory Norton’s Theorem Superposition Theory Thevenin’s Theorem Related Topics Resistor Circuits Electrical Electrical and Electronic Weblinks

Voltage

Voltage is an alternative term for the electrical potential difference between two points. An electromotive force (EMF) is the voltage produced by a source of energy such as a battery or generator. The SI unit for electrical potential difference is the volt. The unit...

Right-hand Corkscrew Rule

The direction of the circular magnetic field around a current carrying conductor may be found by visualising a right-handed corkscrew being rotated so that the point of the corkscrew moves in the direction of the flow of conventional current. The clockwise rotation of...

Resistors in Parallel

The resistance of two or more parallel resistors will be less than the smallest of the individual resistors, since each resistor allows an alternative path for current flow. In general, the reciprocal of the total resistance (1 / RT) is the sum of the reciprocals of...