This is a very simple LED dimmer circuit which has 2 transistors, 1 resistor and 2 potentiometers. Typical segment displays LEDs consume around 25 mA for each segment and should be limited to this ...

Like the circuit in Figure 1, it operates with 3.6 to 6.5V inputs and drives one LED with currents as high as 1A. For the single-LED circuit of Figure 3, the starting voltage of the MAX1685 defines ...

Find out how you can change a circuit by adding items like switches with this Bitesiz KS2 science animation and a fun activity.