I'm trying to create a power source switch using a relay. This's supposedly will be used for my Raspberry Pi. So what I want to do here is :
- Create a backup power source with battery that will replace the main power if it's failed/off
- Add a capacitor to holds charge, so when the relay is switching, the power will not completely cut off
Here's my schematic:
I already tried to create this, but the problem is when the main power is cut off, the output still drops and then backs up to 5V. So I've assumed the capacitor is not doing its job.
But strangely, if I cut both of the power, the output still shows 5V (and slowly going down), so this means the capacitor actually holds a charge, right? Then why when the relay switching, the power still temporary went down? Do I did this incorrectly?