Battery-free 5 volt project power

Step 15 Testing

Toggle the switch towards the faceplate. That is the On position.

Hold the dynamo power supply in your left hand and crank the handle with your right hand. Around two rotations per second is good. You should encounter a little resistance -- that's the capacitor charging. After a few seconds the voltage will be high enough the light the LED. As the capacitor approaches 5V, the resistance will drop. At that point, the capacitor is charged.

If you have a complementary adapter with power leads for your output cable, you can connect it to a voltmeter. Around the point where cranking resistance drops you should see that voltage approaches and stays near 5V.

If you encounter resistance but the LED does not light, check the faceplate connections. If the output voltage seriously overshoots 5V, make sure the electrolytic capacitors are correctly soldered. If you do not encounter any resistance and it clearly isn't working, it's possible there's a short somewhere in the step-up converter circuit.