120 likes | 268 Views
Circuits. R. Pearson PMHS 2007. Ohms Law. For many conductors of electricity, the electric current which will flow through them is directly proportional to the voltage applied to them. I is measured in Coulombs/Second. So what is a resistor, conductor, and Insulator?.
E N D
Circuits R. Pearson PMHS 2007
Ohms Law • For many conductors of electricity, the electric current which will flow through them is directly proportional to the voltage applied to them. I is measured in Coulombs/Second
So what is a resistor, conductor, and Insulator? • A resistor is a circuit element which retards the flow of electrons. Why would we want to do that? • A conductor is a material the obeys Ohm’s law. • What is an Insulator?
Resistance effects • Series (one after another) • Parallel (each end hooked together)
Series Circuits • Voltage drops in each resistor V=IR • Total Voltage drop around circuit is the applied Voltage. Why? • If you roll down a hill how far will you go? • R=R1+R2+R3 • Find the total current to find voltage drops
Parallel Circuits • Voltage is constant • Why? Well if everyone starts at the top of the hill how far will they all fall. • Use constant voltage to find the current in each resistor or the current to find the resistance. • V=IR • V=IP
Parallel Circuit Elements! Series
Try the following! • QuestionAn emf source of 6.0V is connected to a purely resistive lamp and a current of 2.0 amperes flows. All the wires are resistance-free. What is the resistance of the lamp?
QuestionThe current flowing in a circuit containing four resistors connected in series is I = 1.0 A. The potential drops across the first, second and third resistors are, respectively: V = 5 V, V = 8 V and V = 7 V. The equivalent resistance of the circuit is R = 30 . Find the total voltage supplied by the battery, and also current, voltage drop, and resistance of each resistor in the circuit.
In the following schematic diagram, find the total current, I.
Combined Circuits • How would you handle a circuit with both parallel and series components. Textbook Page 575 section 18-2 Pg 592 Probs 5, 6, 22, 25 Kirkoff’s Laws Or just collaps circuit elements and keep adding