RC/RL Applications

How to Use

1. Select an application using the tabs at the top.
2. Adjust the component sliders (R and C or L) to see how timing changes in real time.
3. Set a target with the orange "Target" slider, then read the required component values in the results panel — green means achievable, red means out of the practical range.
4. Click "Animate" to see the circuit behavior animated on the graph.

Applications

Tab	Circuit	Key Formula
Camera Flash	RC charging loop	\(t_{98\%} = 5RC\)
Timer (555)	555 monostable	\(t = 1.1RC\)
Relay Protect	RL inductive kickback	\(\tau = L/R\)
Audio Coupling	RC high-pass filter	\(f_c = \frac{1}{2\pi RC}\)

Learning Objective

Students will design RC or RL circuits to achieve specific timing requirements by:

1. Choosing a target timing value (pulse width, charge time, cutoff frequency, or decay constant)
2. Using the universal relationship \(x(t) = x(\infty) + [x(0^+) - x(\infty)]\,e^{-t/\tau}\) to select component values
3. Verifying the design meets real-world component constraints

Design Procedure

For any first-order RC/RL circuit:

1. Identify the timing formula (column 3 above)
2. Pick one component to hold fixed (e.g., keep C = 10 µF)
3. Solve for the other: rearrange the formula for R or L
4. Check the result against practical component ranges