I'm newbie to electronic circuit. got a weird issue and have no idea why it happens.
I can drive a sg90 servo motor by a USB connected 5v power source with no problem. but when I connect the servo motor to my new bought DC supply, it just doesn't work!
I'm pretty sure I've set the right voltage (5V with limit to 6V). The only time point I can make the motor work is by connect/disconnect the power source from the dc supply. I can't drive the motor by the PWM signal sent from my esp8266.(it did work when i'm using USB power).
i can't think of a reason why... thx in advance!