At 3/21/2009 06:20, you wrote: >Hi Bob, > >Cut a long story short .. looks like I did not actually finish the circuit >which with my memory is no surprise. > >While working on the second build have found that the 1500 caps between >pins 1 and 5 are missing as are the connections to pins 4 and 11. I think >the reason was that I did not know what the values were exactly. > >Sorry about this but could you tell me what the value is. > >Regards, >Doug - GM7SVK
The cap values are properly called out on the schematic. Pins 4 & 11 are the supply connections for the op amp. Pin 4 is +12V & pin 11 is ground. BTW, although the TL084 should work fine, there are better op amp choices available these days. I personally like the TLV2374 for its rail-to-rail in/out capability, low crossover distortion & low cost. Then again if all you have in your parts bin is an LM324 it should work fine for testing purposes. Bob NO6B
