Electric circuits: series and parallel

Quantities

• Current (I): flow of charge, measured in amperes (A) with an ammeter connected in series.
• Voltage (V): the push that drives current, measured in volts (V) with a voltmeter connected in parallel.
• Resistance (R): opposition to current, in ohms (Ω).

Ohm's law: V = I x R. A 12 V source with a 4 Ω resistor gives I = 12 ÷ 4 = 3 A.

Series circuit

Components are in one path.