Switching power supply cause blink in LED?


2016-03-15 9:50 pm
Hello, I am a novice tinkerer, and trying to power a simple circuit with a switching power supply which has worked great up until I added a toggle on/off switch with a simple +/- wiring configuration. I hooked the wires from the switch to the power supply accordingly (I think), and when in the "on" position the switch works fine. However, when in the "off" position, the LED on the power supply blinks periodically every second or so (although the circuit LED remains off). Someone told me this might be because I am using a switching power supply, is this true?


Paid Member
2007-09-15 8:14 am
Two things come to mind... and its always difficult to say without actually seeing the configuration.

1/ Check that the switch isn't actually shorting the power supply output when you set it to off. You can easily check by turning off the mains and then measuring across the PSU output with your meter on ohms.

Some switching supplies would go into a burst mode if running into a short (rather than just blowing up)

2/ The opposite can also happen. Some switching supplies need to see a minimum load to operate properly. Again, they can start firing in a burst mode.