Document page
igcse physics notesprinted 100 · PDF 100
124 pagesrevision 46936
printed 100 · PDF 100
Page image rendered from the stored file at 110 dpi; it sharpens as you zoom. Outlines are placed from each region’s stored position on the page (612 × 792 pt).
readable
Source of this text: embedded text layer. The better of the embedded text and OCR is kept.
100
Electric circuits:
Series
● Components are connected end to end in one loop
● The same current flows through every component
● The potential difference is shared across each component (i.e. the sum
of the p.d.s across
the components are equal to the total p.d. across the supply).
● The total resistance is the sum of the resistances of each component RT
= R1 + R2
● The combined e.m.f. of several sources in series is the sum of the
individual e.m.f.s
Parallel
● Components are connected to the power supply in separate branches
● The current is shared between each branch (i.e. the sum of the currents
in the separate
branches is equal to the current through the source)
● The potential difference is the same across every branch
● The total resistance of two resistors in parallel is less than the resistance
of either resistor by itself, and is given by R1*R2/R1+R2
Advantages of parallel circuits:
If one component breaks, current can still pass through the rest.
Components of Circuits:
A potential divider circuit consists of two resistors connected in series to
obtain a smaller voltage than supplied.
The voltage across a certain component is given by 𝑉𝑜𝑢𝑡 = 𝑉𝑖𝑛 ×𝑅/𝑅𝑇
where Vin is the source voltage, R is the resistance of the component and
RT is the total resistance.