Learn

Electronic circuits involve the manipulation of voltages, currents, and resistances. Knowing how these three properties relate to each other is a foundational part of circuit design. These relationships are described using the equation, Ohm’s Law.

The formula of Ohm’s Law is as follows:

$V = I × R$

Where:

• V = voltage expressed in Volts
• I = current expressed in Amps
• R = resistance expressed in Ohms

Note: Voltage is sometimes represented in Ohm’s Law using “E”

If two values are known, we can use algebra to reconfigure Ohm’s Law and calculate the third value:

To find the current, divide voltage by resistance.

$I = V ÷ R$

To find resistance, divide voltage by current.

$R = V ÷ I$ The above schematic has a voltage source with an unknown voltage. There is a current, I = 2A through a load resistor, R = 4.5Ω. Using Ohm’s Law we can find the voltage of the circuit’s voltage source:

$V = I × R$
$V = 2A × 4.5Ω$
$V = 9V$

The above example contains one voltage source and one load resistor. In general, a circuit’s load will consist of multiple components. In this case, you will need to find out how much of the source voltage is used by each component when applying Ohm’s Law.

### Instructions

1.

Use the given values in Circuit 1 and Ohm’s Law to find the voltage (V) across the voltage source.

Type your answer below Answer 1. It should look like V = your answer

2.

Use the given values in Circuit 2 and Ohm’s Law to find the current (I) through the circuit.

Type your answer below Answer 2. It should look like I = your answer

3.

Use the given values in Circuit 3 and Ohm’s Law to find the resistance (R) of the resistor.

Type your answer below Answer 3. It should look like R = your answer