PAGE 085 OF 150 · TIMERS, FLASHERS & DIMMING
Analog Dimming vs PWM Dimming
Analog changes current; PWM changes pulse width.
LED SYMBOLTriangle points from anode to cathode; the arrows show light leaving the part.
Two ways to dim
Analog dimming lowers the steady LED current. PWM dimming switches the full current on and off rapidly.
Comparison
- PWM keeps colour consistent because current is always at full value when lit.
- Analog dimming is flicker-free and creates less electrical noise, but colour can shift at low current and control is harder at very low levels.
- PWM needs a fast switch, and its edges can cause interference.
Many drivers combine both: analog at higher levels and PWM at the dim end for the best range.
REMEMBER
Switching an LED on and off quickly can look like steady dimmer light.Try it yourself
Sketch the circuit on paper first, calculate the values, then build it on a solderless breadboard using a low-voltage supply. Measure with a multimeter before you make anything permanent.
Explore LED clocks, stopwatches and electronics at cosycom.com.