Series Circuit Rules
Electrical Circuits - OCR A-Level Physics
- CurrentThe rate of flow of chargeA property of matter that causes it to experience a force in an electromagnetic field. Measured in coulombs (C).. Measured in amperes (A). is the same through every component in series.
- The total p.d. equals the sum of p.d.s across each component.
- P.d. is shared in proportion to resistanceThe opposition to currentThe rate of flow of chargeA property of matter that causes it to experience a force in an electromagnetic field. Measured in coulombs (C).. Measured in amperes (A). flow. The ratio of potential difference to currentThe rate of flow of chargeA property of matter that causes it to experience a force in an electromagnetic field. Measured in coulombs (C).. Measured in amperes (A).. Measured in ohms (Ω).: larger R gets larger V.
- Total resistanceThe opposition to current flow. The ratio of potential difference to current. Measured in ohms (Ω).: simply add them up.
$$\begin{aligned}
V &= V_1 + V_2 + V_3 \\
&= IR_1 + IR_2 + IR_3
\end{aligned}$$
$$R_{\text{total}} = R_1 + R_2 + R_3 + \ldots$$
Three resistors connected in series with a cell
Single loop with R_1, R_2, R_3 in line. Same current I through all. V_1 + V_2 + V_3 = EMFElectromotive force. The energy transferred per unit charge by a source in driving charge around a complete circuit. Measured in volts (V)..
Common Mistake
MEDIUM
Wrong: Thinking the current gets 'used up' as it passes through each resistor.
Right: Current is the same everywhere in a series circuitA circuit in which components are connected end-to-end so the same current flows through each component.. Only p.d. is shared.
Right: Current is the same everywhere in a series circuitA circuit in which components are connected end-to-end so the same current flows through each component.. Only p.d. is shared.