1. EET 110 - Survey of Electronics Chapter 11 - Ohms Law

2. b Electrical Units and prefixes Voltage - V, emf or E - in VOLTs (V)Voltage - V, emf or E - in VOLTs (V) Current - I in AMPEREs (A)Current - I in AMPEREs (A) Resistance - R in Ohms (  )Resistance - R in Ohms (  )

3. b Prefixes billion - 10 9 - giga - Gbillion - 10 9 - giga - G million - 10 6 - mega - Mmillion - 10 6 - mega - M thousand - 10 3 - kilo - kthousand - 10 3 - kilo - k one - 100 -one - 100 - one thousandth -.001 - 10 -3 - milli - mone thousandth -.001 - 10 -3 - milli - m one millionth -.000001 - 10 -6 - micro - one millionth -.000001 - 10 -6 - micro -  one billionth - 10 -9 - nano - none billionth - 10 -9 - nano - n one trillionth - 10 -12 - pico - pone trillionth - 10 -12 - pico - p

4. Units b To convert amperes (A) to milliamperes (mA), move the decimal point three places to the right..012A = 12 mA.012A = 12 mA b To convert mA to A, move to the left 450mA =.45A450mA =.45A

5. Chapter 11- Ohms Law b The basic form of ohms law is

6. b Alternately this is b The current, (I) in a circuit is directly proportional to the applied voltage (V) and inversely proportional to the resistance (R)

7. Alternate forms b Three forms of Ohms law b I = V/R b V = I x R b R = V/I

8. To calculate current b if V = 120v, R = 15 ohms, what is the current?

9. Voltage b If a DC generator delivers 2.5A to a lamp that has 50ohms resistance, voltage must be?

10. Resistance b Suppose an electric kettle draws current of 8A when connected to 120v. What is the resistance?

11. Ohms Law Circle V IR

12. Power Formulas b Power in watts = volts x amperes P = V x IP = V x I b using ohms law we can get P = I 2 RP = I 2 R P = V 2 / RP = V 2 / R