Simple ESR meter

 Almost a copy from here.

 

Only added provision for self "TEST", that is; the switch disconnects the terminals and connect internally to know resistor values via rotary switch (minimum 2 Ohm since had nothing smaller at the time). Also add zeroing via a pot on R24 place.

Diagram from the original site:

 

Inside:

 

and during testing:

Works nice, handy for testing old caps.

Have a nice day!