✅ A simple but reliable device for checking the TL071 and TL081 chips. Volumetric installation! ✅ 

With an operational amplifier, the inputs must be terminated with resistors, especially if they are unijunction transistors. As there is also no feedback resistor, the gain is set to maximum. Pressing the buttons opens the inputs! This cannot work.

12 out of 20?... that seems a little unrealistic. But I may use this to test some that I'm expecting to arrive soon. Thanks