Download Transformer problems (Due Tuesday 25th March (PAYDAY

Honors Electricity & Ohm’s Law Exam Part II
Directions: Please choose 1 transformer problem to diagram and solve. Be sure to label all
parts, determine if it’s a step up or step down and show all work for calculations. There
are built in bonuses for those who attempt the more difficult problems; however, the
grading is based on this problem being 10 points.
Transformer problems
EASY (10 points) A transformer has 10 turns on its primary coil and 30 turns on the secondary.
1. If the primary voltage is 2 V, what is the secondary voltage?
2. A transformer has 20 turns on the primary coil and 2 turns on the secondary. If the
primary voltage is 100 V, what is the secondary voltage?
MEDIUM (15 points) A transformer is being used to play a game boy. Mains electricity is 220
V and the game boy needs 6 V.
1. If the transformer has 10 coils on its secondary coil, how many does it have on its
primary?
2. Explain why electricity is transmitted at very high voltages
HARD (20 points) An ideal transformer has 40 turns on its secondary coil and 3200 turns on its
primary.
1. Calculate the secondary voltage if a 220 V a.c. supply is connected to the primary coil
2. Calculate the current through a 15 Ohm resistor connected to the secondary coil.
3. What current must flow through the primary coil when the 15 Ohm resistor is connected
to the secondary coil?
Directions: Everyone must complete #1 on the circuit problems below. Be sure to diagram
the circuit, label the appropriate parts, and show all work on calculations. Once complete,
choose any additional 2 problems to complete.
1. A circuit is set up with two parallel resistors, each of a resistance of 250Ω.
a. What is the total resistance for this circuit?
b. If another resistor of resistance 300Ω is added in series with these two parallel
resistors, what is the total resistance?
c. If a voltage of 120V is put across the circuit in b, what will the current be in the
circuit?
2. A series/parallel circuit is set up as shown below. Find the total resistance of the circuit
and the current in the circuit
8Ω
25Ω
15Ω
Ω
8Ω
12V
3. Find the total resistance and the current for the circuit below:
25Ω
10Ω
Ω
15Ω
30Ω
6V
4. Find the total resistance and the current for the circuit on the back:
6Ω
10Ω
Ω
5Ω
8Ω
18V
5. Find the total resistance and the voltage for the circuit below:
10Ω
30Ω
25Ω
Total
current in
the circuit
=2A
Ω
15Ω
6. Find the total resistance and the voltage for the circuit below:
15Ω
3Ω
Total current in
the circuit =
2.4 A
45Ω
Ω
8Ω