DC CIRCUIT TERMINOLOGY
Basic DC Theory
Temperature Coefficients for Various Materials
Coefficient, W per °C
For a given material, a may vary with temperature; therefore, charts are often used to describe
how resistance of a material varies with temperature.
An increase in resistance can be approximated from equation (2-2).
higher resistance at higher temperatures
resistance at 20oC
temperature rise above 20oC
Each electrical circuit has at least four basic parts: (1) a source of electromotive force,
(2) conductors, (3) load or loads, and (4) some means of control. In Figure 13, the source of
EMF is the battery; the conductors are wires which connect the various component parts; the
resistor is the load; and a switch is used as the circuit control device.