Section 2. Connecting Devices

2.1 Voltage Sources

Most electrical circuits accept some kind of an electrical supply or signal (usually a voltage) from another device (e.g. a power supply or a signal generator). Such a device is usually represented in circuit diagrams as a voltage source. This hypothetical component, drawn using one of the symbols shown in the figure, produces the same voltage regardless of the circuitry to which it is connected. Real devices never do this. The more current you draw from them the less voltage they produce. This may be represented by placing a hypothetical resistor in series with the voltage source.