Musicmanager
Well-Known Member
Hi Guys
Remember I'm a novice .. ...
I've built an ESR meter from a schematic I found on the web .. .. copy is attached.
Although intended to be powered by a 9v battery I set it up with my bench power supply because it has current limit protection and I thought ... if I've done my usual and put something in the wrong place .. .. .. you know what I mean !
Well, as anticipated it trips out the current limit immediately and I've thoroughly checked my work is exactly as the schematic ..
My question .. .. top left hand corner of the schematic shows 9v supply coming from the battery via a switch with two 10K Resistors ( R1 & R2) which I recognise as a voltage divider, feeding into pin 3 of Op Amp A, effectively pin 4 is 4.5v; pin 11 is -4.5v and pin 1 is Gnd or virtual ground as the author calls it.
I think the supply rail between the R1( marked V+) and Pin 4 of the Op amp (marked 4.5v) should be cut otherwise the supply will maintain 9v at Pin 4 ????
Any advice would be welcome ..
S
Remember I'm a novice .. ...
I've built an ESR meter from a schematic I found on the web .. .. copy is attached.
Although intended to be powered by a 9v battery I set it up with my bench power supply because it has current limit protection and I thought ... if I've done my usual and put something in the wrong place .. .. .. you know what I mean !
Well, as anticipated it trips out the current limit immediately and I've thoroughly checked my work is exactly as the schematic ..
My question .. .. top left hand corner of the schematic shows 9v supply coming from the battery via a switch with two 10K Resistors ( R1 & R2) which I recognise as a voltage divider, feeding into pin 3 of Op Amp A, effectively pin 4 is 4.5v; pin 11 is -4.5v and pin 1 is Gnd or virtual ground as the author calls it.
I think the supply rail between the R1( marked V+) and Pin 4 of the Op amp (marked 4.5v) should be cut otherwise the supply will maintain 9v at Pin 4 ????
Any advice would be welcome ..
S