I'm designing a tiny controller box which needs DC power for a micro. I want to bring in a single AC power cord in and thru transformer/rectifier/capacitor make it into DC, finally there will be a regulator to give me 5VDC.
I had a transformer which take 120VAC down to 16VAC, and my big Cap connected the output of the recifier is a 10KuF 25V cap. When I plugged in this part of the circuit, the output of the DC charged to 25V and upon unplugging, it stayed at 25V. Luckily, I hadn't connected the 5VDC regulator and logic parts of the controller yet.
My questions are:
1) Why is DC output at 25V and not 16V.
2) What is a safe way to have the big cap drain?
3) Is the Cap too big? what should I use instead?
Thank you,
I had a transformer which take 120VAC down to 16VAC, and my big Cap connected the output of the recifier is a 10KuF 25V cap. When I plugged in this part of the circuit, the output of the DC charged to 25V and upon unplugging, it stayed at 25V. Luckily, I hadn't connected the 5VDC regulator and logic parts of the controller yet.
My questions are:
1) Why is DC output at 25V and not 16V.
2) What is a safe way to have the big cap drain?
3) Is the Cap too big? what should I use instead?
Thank you,