CIRCUIT MODULE FOR SELECTIVE MAGNETIC-FIELD SCANNING IN MAGNETIC-RESONANCE SPECTROMETERS

An inexpensive electronic circuit module has been designed and constru cted to replace the ''field scan potentiometers'' of magnet power supp lies used in old EPR spectrometers. Linearly varying AC and DC error v oltages are generated by this circuit module. Apart from the obvious a dvantages gained by changing the mechanically controlled scanning to d igitally controlled electronic scanning, this circuit also has the abi lity to scan selected field regions, with facility to go from one sele cted field region to another field region rapidly and automatically, ( similar to the ''tab'' facility in a typewriter) thereby saving the ti me spent in the collection of useful data. In our design the bouncing problem associated with ''key'' operations has been eliminated by the use of appropriate software control. We have evaluated the performance of this circuit module by using it with a Varian Fieldial power suppl y.