What does it mean for two components to be in series?
Two components are in series if the same current flows through each – i.e. there is no branching path between them.
In a series circuit, what happens to the current?
The current remains the same through all components in the series.
What does it mean for two components to be in parallel?
Two components are in parallel if they share the same two connection points (nodes) – which means they have the same voltage across them.
What is the equivalent resistance of resistors in series?
It is the sum of the individual resistances:
$$
R_{\text{eq}} = R_1 + R_2 + \cdots + R_n
$$
How do you find the equivalent resistance of parallel resistors?
By the reciprocal sum formula:
$$
\displaystyle \frac{1}{R_{eq}} = \frac{1}{R_1}+\frac{1}{R_2}+\cdots
$$
What does the voltage divider equation determine?
It calculates how a source voltage is proportionally divided across the resistors in series (according to their resistance values).
What voltage relationship exists for devices connected in parallel?
All devices connected in parallel experience the same voltage across their terminals.
What is the equivalent resistance of resistors in parallel?
he reciprocal of the sum of reciprocals of each resistance (which will always be less than the smallest resistor).
What does the current divider equation determine?
It tells how a total current splits among parallel branches, in proportion to the conductances (or inversely to resistances) of those branches.
What is a short circuit?
A near-zero resistance path (often unintended) that can bypass other elements, causing a very large (potentially damaging) current.
What is a fuse and its purpose in a circuit?
A fuse is a thin wire that melts (“blows”) when current exceeds a specified limit. By blowing, it opens the circuit to protect the wiring and components from the excessive current.
How do we choose an appropriate fuse or circuit breaker rating for a circuit?
Choose a rating slightly higher than the circuit’s expected maximum normal current, yet low enough that it will blow/trip on a meaningful overcurrent. In practice, you provide a safety margin above normal operating current but still protect against surges.
What are the ECE 315 rules for circuit breaker design?
Calculate the maximum current, multiply by 1.1 for margin, and round up to the nearest whole or half value using engineering notation.
