Resistance

1. Low at high frequency Low at low frequency Ω Ω f f Resistance Impedance Energy Storage DC Direct Current AC Alternating Current Electric Field Capacitance Magnetic Field Inductance Resistor R Ohms Reactance Z Ohms Inductor L Henry Capacitor C Farad Oppose flow of DC current Oppose flow of AC current Coil of wire 2 or more conductive surfaces separated by an insulator Ohms Ohms Potentiometer R Ohms Variable Resistor, varies resistance like adjusting volume

2. Collector Collector Source Base Base Gate Drain Emitter Emitter FET NPN PNP Field Effect Transistor Diodes Transistors Anode Cathode (marked with a stripe) One way current Can be used to rectify AC to DC current Electronically control flow of current On/Off Amplify (gain) (3 layers of semiconductor) Visual Indicators Switch Relay Single Pole Single Throw LED Light Emitting Diode Lamp Connect – Disconnect Circuits A switch controlled by an electromagnet

3. Fuse Transformer High voltage Protect from current overload Interrupt power in case of overload Protects from excessive current that may cause a fire Low voltage Commonly used to change 120V AC house current to a lower AC voltage Other Schematic Symbols Integrated Circuit Device that combines several semiconductors and other components into one package Battery Antenna Variable inductor

4. Resonant or Tuned Circuit Schematics Inductor and Capacitor together forms filter Show connection of electrical components Hint: in this schematic transistor 2 controls current flow to the lamp.