Ham Radio General Class Practice Test

What is the inductance of three 10 millihenry inductors connected in parallel?

1. 0.30 Henrys

2. 3.3 Henrys

3. 3.3 millihenrys

4. 30 millihenrys

The correct answer is: 3.3 millihenrys

To determine the inductance of inductors connected in parallel, you need to apply the formula for combining inductors in parallel. For n inductors with the same inductance value (L), the total inductance (L_total) can be calculated using the formula: \[ \frac{1}{L_{\text{total}}} = \frac{1}{L_1} + \frac{1}{L_2} + \frac{1}{L_3} \] Given that all three inductors each have an inductance value of 10 millihenries (mH), the formula simplifies to: \[ \frac{1}{L_{\text{total}}} = \frac{1}{10 \, \text{mH}} + \frac{1}{10 \, \text{mH}} + \frac{1}{10 \, \text{mH}} \] Calculating this gives: \[ \frac{1}{L_{\text{total}}} = \frac{3}{10 \, \text{mH}} \] Thus: \[ L_{\text{total}} = \frac{10 \, \text{mH}}{