Okay i've done some playing around with this circuit and i cannot get it to work for my application. I have pin 26 grounded because it will not be measuring voltages. i am not using it as a typical dmm i'm using it to display a voltage in a circuit that will always be positive. I am using the LM2907 frequency to voltage converter below and have it configured so that the output voltage is linearly proportional to the input frequency (ie 200mv ~ 200hz) the max freqency i'd measure would be about 1200Hz which would correspond to 1.2v work perfectly on the 2v scale and i would just leave the decimal points unconnected. I have hooked up the DVM circuit, and did a test on a voltage divider to see if it was measuring correctly and it did measure the voltage, but i only had to connect terminal one to the voltage point and did not connect terminal 2 to anything and the voltage displayed correctly. (this is btw with the negative supply grounded). The LM2907 freq to voltage converter circuit i have completely working and outputing the corresponding voltage when i use a regular multimeter, but i would like to integrate this circuit with it to have a permanent display. anyone have any ideas what i'm doing worng? I tried the circuit suggested in the appnotes about the CMR problem but i couldnt get that to work either.
link to 7107 appnote:
https://www.electro-tech-online.com/custompdfs/2003/11/an9609.pdf
**broken link removed**
**broken link removed**
so close!
thanks
bonanz[/url]
link to 7107 appnote:
https://www.electro-tech-online.com/custompdfs/2003/11/an9609.pdf
**broken link removed**
**broken link removed**
so close!
thanks
bonanz[/url]