Darn... > pin 5 voltage will be > 'clamped' by the diode at the Iabc input, so will be around > 0.7V or so ...about 0.7V *above the negative rail* of course! Tim __________________________________________________________ Tim Stinchcombe Cheltenham, Glos, UK email: tim102 at tstinchcombe.freeserve.co.uk www.timstinchcombe.co.uk