# Diode for overvoltage

This may appear as a very simple question but I am looking for a cross reference for the BAT 54 diode. Here were I live, I can't get that diode. The circuit that I am using is below, so you have an idea what I am using it for. It is basically for connecting a battery to an ADC converter. If the battery exceeds the 5V input maximum voltage, the diode protects the pic. • Sorry but the diode won't protect the PIC because the 7805 won't stop voltages rising above 5 volts on its output (due to current through the diode). Dec 14, 2022 at 16:58
• @Andyaka So how i can protect the pic from connecting something above 5v? Dec 14, 2022 at 17:07
• Something above 5 volts might be 100,000 volts so, to start with, you need to be realistic about what might happen. If it's (say) 10 volts then R1 will limit the current to a value of 0.5 mA and this could be acceptable if you read the data sheet for the PIC. Now, a diode isn't needed but, you have to make a decision about that voltage. Dec 14, 2022 at 17:11
• @Andyaka . I calculate the max voltage input, its something about 23v, it would be like an amp in the input Dec 14, 2022 at 17:21
• Use a voltage divider then diode clamp that. Any Schotky diode should be sufficient. Dec 14, 2022 at 17:36