Electronics Engineering: Vocab and Equations

Voltage

100

What is the measurable unit for voltage?

Volts

200

What is the equation for voltage?

V = I x R

300

What is the voltage at the second resistor? Use a unit with your answer?

V = I x R ---> 2 amps x 20 ohms = 40 volts

400

What is the total voltage of the circuit? 

V = I x R ---> need to find total R first

Rt = 3 + 10 + 5 = 18 ohms ---> back to equation

V = 3amps x 18 ohms = 54 volts

500

What is the voltage drop of each resistor? You will need to calculate the total current first. 

I = V/R ---> 9v/450 ohms = 0.02amps

R1 - V= IxR  ---->  0.02 x 100 = 2 volts

R2 - V= IxR  ---->  0.02 x 300 = 6 volts

R3 - V= IxR  ---->   0.02 x 50 = 1 volt

Current

100

What is the measurable unit for current?

Amperes (amps)

200

What is the abbreviation for the current? 

Used in equations (one letter) 

I

300

What is the equation for current?

I = V/R

400

How much current is flowing through the first resistor if the circuit's total current is 2? Use a unit in your answer. 

2 amps

500

Calculate the total current given there is 9V and R1 is 3 ohms, R2 is 10 ohms, and R3 is 5 ohms. Use a unit with your answer. 

Rt = 3 + 10 + 5 = 18 ohms

I = V/R ---> 9/18 = 0.5 amps

Resistance

100

What is the measurable unit for resistance?

Ohms

200

What is the abbreviation for resistance? Used in equations. 

Ω

300

What is the equation to find resistance given the voltage and current?

R = V/I

400

What is the total resistance of the circuit?

232 ohms

500

A resistor has 1.5 amps and 12 volts running through it, what is the resistance of the resistor?

Answer with a unit on your answer. 

R = V/I    ---->   12/1.5

R = 8 ohms

Series Circuits

100

How many resistors are in this circuit?

3

200

What is the resistance of resistor 2?

10 kiloohms 

300

What is the load in this series circuit?

2 light bulbs

400

What is the voltage in the third resistor?

Find the total current so we can use it - I = V/R

Rt = 15 + 20 + 5 = 40 ohms

I = 80/40 = 2 amps (2 amps through all resistors)

V R3 = 2 amps x 5 ohms = 10 volts

500

What is the resistance of each resistor if...

R1 has 6.6V, R2 has 4.4V, and R3 has 2V. The total current is 0.02A.

R1 = V1/I1 = 6.6 volts/0.02 amps = 300 ohms

R2 = V2/I2 = 4.4 volts/0.02 amps = 220 ohms

R3 = V3/I3 = 2 volts/0.02 amps = 100 ohms

Parallel Circuits

100

How many resistors are in this circuit?

3

200

What is the load of this circuit?

3 light bulbs

300

What is the equation for finding total resistance in a parallel circuit? Let's say there are 3 resistors.

1/Rt = 1/R1 + 1/R2 + 1/R3

400

What is the voltage flowing through each branch of this parallel circuit?

9V - It is the same as the total voltage

500

How much current is flowing through each resistor?

1/Rt = 1/20 + 1/40 + 1/60

1/Rt = 6/120  + 3/120  + 2/120

1/Rt = 11/120 ---> Rt/1 = 120/11 ---> Rt = 10.9 

Find It ---> I = V/R ---> I = 120/10.9 = 11

I R1 = 120/20 = 6amps

I R2 = 120/40 = 3amps

I R3 = 120/60 = 2amps

Double check current adds up to 11 ---> 6+3+2