2. 8.3 Practical Circuitry

3. How do we wire our houses? Individual elements are wired in parallel Devices can be turned off/on without affecting others Currents are relatively high Parallel elements are wired in series loops Keeps currents from getting TOO high What happens when we plug too many things into the same loop? Since all sockets are parallel, the resistance drops Current increases We sometimes say the outlet “shorts out”

4. What is a circuit breaker? Basically, a circuit breaker is a switch that flips itself if the current gets above a certain level A fuse is a device that breaks when the current gets above a certain level

6. What is an integrated circuit? Most devices use integrated circuits built on silicon circuit boards The particular design is CMOS technology These circuits use electricity to perform logic functions The major device in an integrated circuit is the transistor Other devices on a circuit board: resistors, capacitors, inductors, diodes Due to complexity and device sensitivity, circuits are first constructed on breadboards, then soldered into place once the design is confirmed resistor integrated circuit LED capacitor diode transistor switch bridge rectifier electret microphone

7. How are different forms of current related? There are two basic types of current: Direct Current (DC): current goes in one direction, from + to – Examples: battery-powered devices, most circuit boards Lower current even at higher voltages Cannot travel long distances due to resistance in wires Alternating Current (AC): current reverses direction Examples: homes, generators Higher current even at lower voltages Can travel long distances because of increased current Why on Earth do we use the more dangerous one in our homes?? Westinghouse (left) and Tesla (right), his most famous employee, developed the first AC-powered devices and plants in the U.S. They produced power quickly and cheaply! Edison was an extremely important inventor and held the patent on the first electrical device ever built – his light bulb ran off DC power.