User manual

14
A1: 200 ms
A2: 400 ms
A3: 800 ms
A4: 1,600 ms
Additionally, the rising numerical values are also output to the PWM output (pulse width
modulation) . The PWM signal is a rectangular signal with a frequency of approx. 16 kHz. The
pulse length is controlled so that the pulse-pause ratio determines the average activation
duration and thus the brightness of the LED. The brightness of the connected LED is controlled
in 15 levels between zero and full brightness.
A PWM signal can be smoothed to a direct voltage with an RC low-pass filter. The PWM-output
thus becomes an analogue output. With this programme, you will receive a direct voltage that
increases gradually from 0 V to 4.5 V. Track the voltage progress wit a meter or an oscilloscope.
Fig. 7: Low-pass filter at the PWM output