Intro to electricity for the Swedish amateur radio course

1. Electricity
Andrew Wallace

2. Overview
 Electricity
 Units
 AC/DC

3.  Height - potential
 Flow - current
 Width - resistance

4. Electricity
 Voltage (EMF) – height
 V in Volts
 Current – flow
 I in (milli) amps
 Resistance – width
 R in Ohms ( )
 Controlling the Flow

5. Controlling the Flow
 U = IR
 U = voltage
 I = current
 R = Resistance
 Ohms Law
 Example :
 I = 10 mA and R = 1 k
 U = 10 mA * 1 k = 10 V

6. Controlling the Flow
 Resistors
 Wire
 Carbon
 Power rating
 Value – colour rings

7. Units
 What sizes do we use to measure things?
 Nano - n
 Micro -
 Milli - m
 Killo - k
 Mega - M

8. Units
T G M k …, m n p
12 9 6 3 -3 -6 -9 -12

9. Voltage
 DirectCurrent (DC)
 Alternating Current (AC)

10. Voltage
 Direct current
 Flow
 Batteries
 cells
 DC generators

11. Voltage
 Alternating
current
 Flow
 AC Generators
 Circles, triangles
and waves!

13. Voltage

14. Voltage
amplitude
Wave length

15. Voltage
 Howmany wave lengths do we have
each second?
 Herts (Hz)
F = 1/t
F = 300 / wave length ( ) in MHz

16. Power
 How much work can we do?
 Power (P)
 Current
 Voltage
 Watts (W)
P = IU

17. Power
I = 2 mA
U=5V
 P = IU = 2 mA * 5 V = 0.01 W
P =5W
 U = 24 V
 I = P / U = 5 W / 24 V = 0.208 A

18. Questions?