PCB_assembled
The IC at the top left is a 555 timer which, along with the TO220-packed MOSFET to its left and associated components, forms the voltage converter for the resistance ranges (12V for the lower ranges, 115V for the megohm range).
The IC at the top right is the op-amp to drive the battery-OK LED.
The IC at the bottom centre is the amplifier to drive the meter.
The 2 large resistors at the top left are the dummy loads for cell testing.
PCB_assembled
The IC at the top left is a 555 timer which, along with the TO220-packed MOSFET to its left and associated components, forms the voltage converter for the resistance ranges (12V for the lower ranges, 115V for the megohm range).
The IC at the top right is the op-amp to drive the battery-OK LED.
The IC at the bottom centre is the amplifier to drive the meter.
The 2 large resistors at the top left are the dummy loads for cell testing.