So it was close to using the latest technology.
With the drop down regulator can also control motors or other loads.
Step 1: The LM2596 DC-DC Buck Step Down Converter Module
A finished LM2596 step down module you can get from about 4 €.
The LED voltmeter makes the voltage setting very comfortable. With the trim potentiometer accurate adjustment is possible.
The operation of LED's must not be exceeded the allowable current. Furthermore, the LED should do not heat above 80 degrees.
The most important data:
Input voltage range: 4-40 v (40 v to limit the highest voltage).
Output voltage range: 1.25V - 37V (decompression mode, input output must be greater than 2 V above).
Output current: 2 A continuous outputs.
Output power: the maximum 15 w.
Grain wave peak: 100 mv.
Voltmeter precision: ± 5 ‰ .
Static power: 20 ma
Button to switch measurement of the input or output voltage and LED indicates the current measurement of the input or output voltage.
Continuously adjustable output voltage range of 1.25V -37V, 4-40V input voltage range.
The input voltage is at least high than the output voltage of 1.5V?.
Step 2: Integration Into Fischertechnik
Step 3: Example of Use
I have used in the example 3 Watt LED. The glued heatsinks are unfortunately undersized. I have therefore limited the LED current to 300 mA. It is sufficient to achieve the desired effect
If you want instead of the LED control motors, it may be better to replace the built-in trimmer by a potentiometer.
Of course, it goes without fischertechnik. But fischertechnik saves me a lot of work in the workshop.