I have a circuit meant to operate an actuator in function of the temperature. The code has been tested and, as long as the actuator is not connected, it does what it is meant to do (tried simulating temperature with serial monitor, and checking the answer of the system), without any error. When I plug the actuator (a 12V DC with Max load 1000N/push from eco-worthy.com), the program starts showing random behaviours (some line of code are executed twice, some other never, finally the behaviour is KO)
The battery used for the prototype is taken from my moto, it is a 12V 8Ah 110A EN FTX9-BS
I started reading about decoupling capacitors then, and tried to add some of the 10nF I had here and there, trying to do it well, but no effect...
I see I should dimension the capacitors, and place them wisely. Reading on the web, I've got that:
- there should a minimum capacitance:
But I don't really know how to exactly measure the amount of current needed by the actuator. Any help?
Anyway I hoped that using 10nF would cover the minimum need
- They should be placed as close as possible to the sensitive IC
I placed a 10nF between the two rails on the top of the breadboard in picture, the 5V (output of the voltage regulator) and ground.
- Often, a big and small bypass capacitor are used, in this case (Big power supply + voltage regulator) the big before the voltage regulator, and the small after, close to the IC
I placed then also 1, then 2, 3 and 4 in parallel (I was trying...) between the two rails on the bottom of the breadboard in picture, the 12V from the battery (from which also the actuator draws current) and ground. But nothing changed
Where and how to use decoupling capacitors here? Does someone of the community here know how to help me? Any contribute and discussion will help Thanks!
29/08/2021 I jumped back in this project after long time, with some capacitors more.
Following the indication of @KASPAROLDENDORFF, I added a flyback diode to the actuator coils (see pic below).
The final circuit look like that:
But still.... it does not work! The circuit gets crazy when the actuator arrives at the end of its run...
Does anybody have a clue of how I can make that work? any contribution is welcomed Is the circuit n5 of the datasheet the one to follow in my case? or rather the 6? if it is the 5, what did I do wrong? if is the 6, any indication?
hope i can solve that with your help