Study Physics notes on D.C. circuits for AS Level. Useful for revision, homework, and exam preparation in Zimbabwe.
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This is the AS Level Physics notes. It is a free notes for revision.
AS Level D.C. circuits By the end of this topic, you will be able to: 20.1 (a) recall and use appropriate circuit symbols (b) draw and interpret circuis diagrams containing sources, swilthes, resistors, ammeters and voltmeters and/or any other type of component referred to in the syllabus (c) define electromotive force (e.m.f.) in terms of the energy transflerred by a source in driving unit charge round a complete circuit (d) distinguish between e.m.f. and potential difference (p.d.) in terms of energy considerations (e) undersand the effects of the internal resistance of a source of e.m.f. on the terminal posential difference 20.2 (a) recall Kirchhoff's first law and appreciate the link to conservation of charge (b) recall Kirchhorfs second law and appreciate the link to conservation of energy (c) derive, using Kirchhoff's laws, a formala for the combined resistance of two or more resistors in series (d) solve problems using the formula for the combined resistance of two or more resistors in series (e) derive, using Kirchhorrs laws, a formala for the combined resistance of two or more resistors in parallel (f) solve problems using the formula for the combined resistance of two or more resistors in parallel (g) apply Kirchhofr's laws to solve simple circuit problems 20.3 (a) understand the principle of a potential divider circuis as a source of variable p.d. (b) recall and solve problems using the principle of the potentiometer as a means of comparing potential differences Starting points - Basic knowledge of appropriate circuit symbols. - Methods for drawing and interpreting circuit diagrams. - Electric corrent is the rate of flow of charge. - A potential difference is required to provide energy to move charge through a device. 20.1 Electrical circuits When reporting an electrical experiment, or describing a circuit, is is essential to know exactly how the components are connected. This could be done by taking a photograph, but this tectinique has disachantages, the photograph in Mgure 194, for example, is not clear and does not show all the components. You could sketch a block diagram, in which the components are indicated as rectangular boves labelled 'cell', 'ammeter', 'reststor', etc. The blocks would then be connected with lines to indicate the wiring. This is also unsatisfactory; it takes a lot of time to label all the boxes. It is much better to draw the circuit diagram using a set of symbols that is recognised by everyone and which do not need …