docs/usecases/uc-8.md
# UC-8 Dimmed light without galvanic isolation
In this scenario the power supply of the raspberry pi and the LED is expected to have common ground output.
![Schematic](led_unisolated_bb.png)
## Configuration
```ini
[mqtt]
host = tcp://127.0.0.1:1883
[pca9685]
address = 0x40
frequency = 1000
[light:light1]
topic = home/light1
pwmpin = PCA9685_40_0
name = Light 1
speed = 200000
ondelay = 1
inverted = true
```
> PCA9685 breakout board from [Adafruit](https://github.com/adafruit/Fritzing-Library/blob/master/parts/retired/PCA9685%2016x12-bit%20PWM%20Breakout.fzpz)