Illustration 30.2: Switches, Voltages, and Complete Circuits

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This Illustration allows you to control the current flow through a circuit using switches (voltage is given in volts). Restart.

You can open and close switches to turn the lightbulbs on and off. (How is this similar to a bulb breaking in Illustration 30.1?) Notice that when bulb 1 is dark (S1 open and the other switches closed), there is no complete path for the current, so none of the bulbs light. Furthermore, there must be 0 V across bulbs 2 and 3, and there is 10 V across the switch S1. Similarly, when bulb 2 is dark (S2 open and the other switches closed), there is a complete path for current flow through bulbs 1 and 3 (and the voltage across each is 5 V). The same reasoning applies to bulb 3 when switch 3 is open. (When all the switches are open, the voltmeter readings can have any value, as long as the sum adds up to 10 V.)

Illustration authored by Anne J. Cox.

Physlets were developed at Davidson College and converted from Java to JavaScript using the SwingJS system developed at St. Olaf College.

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