Why does Kirchhoff’s Voltage Law apply?
Because of energy conservation – in any closed loop the net energy change is zero, so all the voltage rises and drops must sum to zero.
What is Kirchhoff’s Voltage Law (KVL)?
KVL states that for any closed loop in a circuit, the sum of all the voltages is zero (total voltage rises equal total voltage drops).
How can KVL be expressed in terms of rises and drops?
The sum of all voltage rises equals the sum of all voltage drops in a loop (voltage rises – voltage drops = 0)
When applying KVL, what sign do we assign to a voltage rise and voltage drop?
Treat a rise (moving from – to + across an element) as positive, and a drop (+ to –) as negative for the KVL sum.
What sign is used for a voltage drop when applying KVL?
Negative – a drop subtracts from the loop sum (consistent with the sign convention above).
Why does Kirchhoff’s Current Law apply?
Because charge is conserved – whatever charge flows into a node must flow out.
What is Kirchhoff’s Current Law (KCL)?
KCL states that for any node (junction), the sum of all currents entering equals the sum of all currents leaving that node.
What is a node?
A point in a circuit where two or more elements are connected by conductors.
What is a loop?
A closed path that begins and ends at the same node without passing through any other node more than once.
What loop direction is used by convention in this course?
Clockwise.
Is power conserved in electrical circuits?
Yes. The total power delivered by sources equals the total power absorbed by the loads (no net loss or gain of power).
What does a ‘negative’ value for current or voltage signify in a circuit?
A negative current or voltage indicates the direction is opposite to the chosen reference direction or polarity.
