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A project log for Numitron Clock

MQTT-enabled Numitron clock with Arduino and ESP8266

harri-ohra-ahoHarri Ohra-aho 09/25/2015 at 16:000 Comments

As everything was connected up and the power was switched on there was a faint whine coming from somewhere in the circuit. I figured the Numitrons were causing some power fluctuations so I added a 100uF capacitor on the power rail. The whining stopped.

The power supply module I have already has capacitors but they didn't seem to help here.

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