What is Ground?

• GND is a reference point
• Where power and current want to go
• What you need for safety
• Active part of antennas and transmission

V, I, R, P

• P = IV, V=IR
• High power is dangerous, not high current/high voltage
• Resistors are rated to handle specific amounts of power
  • Dissipates power as heat
• Reading a resistor:
  • Stripe 1: first digit, Stripe 2: second digit, Stripe 3: multiplier, Stripe on opposite side: tolerance (if none, +/- 20%)
  • Test will provide resistor colour codes
• Test might have questions like: 100 ohm resistor or 2x200 ohms in parallel?
  • If they’re both rated for the same power, two in parallel is better than a single one because you have less power on each

Misc

• Diodes: only allow current to flow one way (in the direction of the arrow)
  • Current goes from anode to cathode
• Conductors and insulators:
  • Gold > Silver > Copper > Aluminum as conductors
  • Insulators: air is decent, porcelain plastic and gas are good
  • Both are affected by temperature