Electrical theory 1.2a - polarity, series/ parallel

To help us repair or design light displays, we need to know some simple electrical theory. Here I'll explain in simple terms what polarity (polarised devices) and series/ parallel connections are.

Polarised devices:  will only work in one direction, as marked. A common example is a battery which has positive and negative terminals. It must be connected correctly into the appliance otherwise it blows the appliance  up. Similarly, a LED has positive (called anode) and negative terminals (called cathode). Light bulbs don't have any polarity and can be connected either way.

Parallel connection: units are connected with common connections for each terminal type, and more than 1 current flows. Batteries are connected with all positive terminals together as shown below. Each battery has a current flowing through it.

 

 

 

Series connection: units are connected in a single line and only 1 current flows. Example: 4 batteries are connected + - + - + -  +- as shown above. (We'll cover volts and amps latter.)

 

Series parallel combination: usually used on low voltage LED strings as shown.

NEXT >> More detail on series parallel circuits