If
there is a complete circuit then the battery provides a potential
difference and pushes current through the circuit.
Batteries always
push current from positive to negative. For a filament lamp this is not
important but many electronic components have to be used the right way round.
This is called being polarised.
Linking current,
voltage, resistance and power
You will
not be expected to use unit prefixes. You are given two quantities and expected
to find the third.
e.g. My radio uses 10 volts and has a resistance of 5
ohms. What current is it drawing from the power supply?
1.
Underline the numbers and units in the question
2. Draw out the
correct triangle
4. Put your finger over the remaining letter
3. Replace
the letters with the numbers given in the question
5. Divide
or multiply the numbers as shown by the triangle
6. Put in the units e.g. Amps, Volts, Watts, Ohms
I=10/5
I
=2
I = 2A
