ELECTRONICS AND SAFETY Scarlett, Dash, Sam, Ashley, and Eric

Circuit Terms  Circuit- complete path of electric current  Voltage- Potential difference  Current- rate of flow of charge, electrons moving along a conductor

DC vs. AC  Direct Current- electrons flow in a straight line (or forward)  Alternating Current (AC)- electrons keep switching directions  In the US, AC is generated at 60 Hz, meaning it alternates 60 times per second

Resistance  Contains two terminals and a semiconductor  Carbon  Ceramic  Size  Width  Length

Resistance ColorNumberMultiplier Black010 0 Brown110 1 Red210 2 Orange310 3 Yellow410 4 Green510 5 But610 6 Violet710 7 Gray810 8 White910 9 ColorTolerance Gold5% Silver10%

Grounding  Limits static electricity  A direct contact to the Earth  The Earth’s voltage is zero  Most AC current

Grounding in portable devices  “A reference point in a circuit from which all other voltages are measured”  Ground plane  Conductive surface  Near power source

Wiring/Circuit Conventions US Conventions TypeColor PowerRed GroundBlack, Blue SignalWhite, Green, Yellow

How Dangerous is Electricity?  Depends on current, voltage, and time exposed  DC current  300 mA is fatal BatteryVoltage (V)Capacity (Ah) AAA AA C D V V12120

How Dangerous is Electricity?  AC current  In normal household outlets, 120 V  1 mA can be felt  5 mA is painful  Above 15 mA, can lose muscle control, fibrillation  70 mA can cause life-threatening irregular heart rhythms

How to Protect Yourself  Soldering  Unplug and turn off soldering iron when not using it  Use the wiring stand when using it Don’t just put down on the table  Clean off the soldering iron after use

How to Protect Yourself  Batteries  Contains acid; can burn eyes, skin, and clothing  If visibly damaged; don’t use it  Careful not to short out battery terminals

How to Protect Yourself  Unplug your circuit from your power source  When plugging it back in make sure everyone working on the circuit is aware  Watch for any exposed metal or wire  Use electrical tape  Double check your circuit  Using incorrect resistors can be dangerous