PowerMonitor PUBLIC

Simple Voltage Monitor using a complementary Mosfet pair.

This circuit will let you measure a voltage source (such as a 12V car battery) without continously draining it. Toggle SW1 to see the scaled voltage output at VM1.

In my final circuit I'll use a DMC2400UV or DMC2053UVT (adds ESD protection) since these are easy to use and delivered in a single package. Instead of SW1, I'll use a 3.3V microcontroller output and then I'll measure at VM1 using an analog input. The values of R3/R4 can be adjusted to scale to any sensible voltage range.