# D.C. circuits – CIE AS Level Physics 9702

Contents:-

• Practical circuits
1. recall and use appropriate circuit symbols as set out in the ASE publication Signs, Symbols and Systematics (example circuit symbols are given in Section 5.5.)
2. draw and interpret circuit diagrams containing sources, switches, resistors, ammeters, voltmeters, and/or any other type of component referred to in the syllabus
3. define electromotive force (e.m.f.) in terms of the energy transferred by a source in driving unit charge round a complete circuit
4. distinguish between e.m.f. and potential difference (p.d.) in terms of energy considerations
5. understand the effects of the internal resistance of a source of e.m.f. on the terminal potential difference
• Kirchhoff’s laws
1. recall Kirchhoff’s first law and appreciate the link to conservation of charge
2. recall Kirchhoff’s second law and appreciate the link to conservation of energy
3. derive, using Kirchhoff’s laws, a formula for the combined resistance of two or more resistors in series
4. solve problems using the formula for the combined resistance of two or more resistors in series
5. derive, using Kirchhoff’s laws, a formula for the combined resistance of two or more resistors in parallel
6. solve problems using the formula for the combined resistance of two or more resistors in parallel
7. apply Kirchhoff’s laws to solve simple circuit problems
• Potential dividers
1. understand the principle of a potential divider circuit as a source of variable p.d.
2. recall and solve problems using the principle of the potentiometer as a means of comparing potential differences

Video (2:41:00 mins)