Currently I am working on a capacitive sensing and actuation system powered both by battery and AC/DC (Wall Wart) power adapter. The system works well when powered by battery and bench top power supply. The system sometimes behaves unpredictably when connected to AC/DC power adapter.
The AD/DC power adapter is 6V and is rated at 1000mA. The capacitive sensing/scanning part of the system draws less than 1mA. The sleep/standby mode draws in the uA range. The actuator needs about 500mA for a very short period and activated sparsely. About 50 times in a 24 hour period. The actuators active time duration is about 30 milliseconds.
I have measured the voltage and current usage with a multimeter, I don’t see any issues.
Any thoughts on what might be causing the instability of the system when used with an AC/DC adapter. Thought on next steps to identify the issue(s) and develop a solution.
Thanks in advance for your help!