What is the formula for ohm’s law?
V = IR or Voltage = Current x Resistance
Why is Ohm’s law helpful/useful?
- understand how electrical equipment works
- install and connect circuits safely
- identify when electrical equipment might be unsafe
- figure out why electrical equipment is not working correctly
- repair faulty electrical equipment
What happens if voltage increases for a constant resistance?
Current Increases proportionally.
What happens if resistance increases for a constant voltage?
Current decreases
What happens if current increases for a constant resistance?
Voltage increases.
Name the three circuit conditions:
Open-Circuit
Closed-Circuit
Short-Circuit
What happens in a closed-circuit?
Circuit is energised
Voltage drop across resistors
What happens in an open-circuit?
No current in circuit
Voltage across open circuit is equal to supply voltage
Circuit is not energised
What happens in a short-circuit?
Circuit is energised
No resistance (apart from conductors resistance)
Peak current output
tripping of protective devices
