Electric Circuits Summary

ELECTRIC
CIRCUITS

, Strength of electric current (I)
 Emf of the battery
 Electrical potential difference (V)
 Electrical resistance


• Ammeter:
• measure current strength through a resistor
• connected in series with resistor
• Has low resistance

• Voltmeter:
• Measure the potential difference across the ends of a resistor
• Connected in parallel across a resistor
• Has high resistance

• Resistance→ a measure of the opposition to current flow in an electrical circuit + measu
ohms.
• If too much current flowing in a circuit- can lead to fuse so resistors are added to mitiga

, OHMS LAW
• Definition: the potential difference across a resistor is directly proportional to the
current strength through the resistor, provided that the temperature remains
constant.




• R = V/I
• V = IR (external resistance)
• I = V/R

, RESISTORS IN SERIES




• Total effective resistance = sum of the separate resistors in circuits


• Each resistor (nvm the size of it) in a series circuit gets the same current strength
IE: I = I =I


• HOWEVER, total potential difference of external circuit → resistors in series are
potential dividers
IE: V = V + V + V