Ciircuits, Diagrams & Symbols Includes:
Circuit symbols overview Resistors Capacitors Inductors, coils, chokes & transformers Diodes Bipolar transistors Field effect transistors Wires, switches & connectors Analogue & functional circuit blocks Logic
The more mechanical items like wires, cable, conenctors and switches also require circuit symbols. Although, in some respects they do not always contribute to the circuit operation in the same way as resistors, capacitors and active devices, they are nevertheless equally important and ahve their circuit symbols.
There is a wide variety of circuit symbols for wires, cables, switches and connectors, indicating the wide variety of options that are available.
|Item Type||Circuit Symbol|
|Wires crossing but not joined|
| Wires crossing but not joined
Often used on older circuits to clarify wires are not joined.
| Wire junction
Note the dot at the junction.
| Two wire junction
Double junction symbol often used for joined crossing wires to remove possiblity of confusion.
| Wires crossing & joined
To avoid confusion with unjoined wires it is normally best practice to use the symbol for the double junction.
|Coaxial cable / feeder|
Typically at the edge of a board, circuit, etc.
|Switch SPST normally closed|
|Switch SPST push button / momentary action|
|Switch single pole 4 way|
Note: abbreviations for switches include:
SPST: Single pole single throw
DPST: Double pole, single throw
SPDT: Single pole, double throw
DPDT: Double pole, double throw
The number of "throws" equates to the number of active positions on the switch. The term throw is normally only used for single and double throw switches, after that the terminology refers to 4 way or 8 way switches, etc.. The number of poles equates to the number of circuits that are switched, i.e. the number of sections within the switch.
More Circuits & Circuit Design:
Op Amp basics Op Amp circuits Power supply circuits Transistor design Transistor Darlington Transistor circuits FET circuits Circuit symbols
Return to Circuit Design menu . . .