Interactive lab

Reading about a trade-off is not the same as feeling it. These three benches let you change the variables and watch the consequences. Every number on screen is calculated from the settings you choose.

Drive a simple battery, resistor and LED circuit. Adjust voltage and resistance and watch the current, power and light output respond in real time.

Controls

Source voltage5.0V

Resistance220ohm

Current

13.6mA

LED power

27mW

Resistor power

41mW

Brightness

68%

Healthy operating point

Current is in the range the LED is designed for. The resistor's job is to set this operating point.

I = (V_source - V_forward) / R
= (5.0 - 2.0) / 220 = 13.6 mA