I am making a project on water level indicator. I've completed the circuit like this:
The circuit is closed through the water.
The problem is even before switching on the circuit, and with terminals not immersed in water, LED glows feebly when connected across 5 VDC source powered from AC source, but not with a 9 V battery.
I want to use the circuit powered from AC, for a long run. I want to know where I am going wrong.