Conventional current and electron flow
Opposite Conventional current (+) Electron flow (-)
Electric current
The rate of flow of electric charge
I = Q / t
Ampere (A)
Ammeter
Ammeter
Series circuit
+ to -
Electromotive force (e.m.f.)
The work done by the source in driving a unit charge around a complete circuit
Volt (V)
e.m.f. = W / Q
Potential difference
The work done to drive a unit charge through the component
Volt (V)
V = W / Q
Voltmeter
parallel
EMF or PD
+ +
- -
Resistance
The ratio of the potential different across it to the current flowing through it
R = V / I
R = p l / A
ohm
Greatest resistance
longest
thinnest