Hi John, John Chung wrote: > Thanks Regulus. Need to open my books for more info > but what you have given me is a head start! Also, I would like to share how we check and calibrated our meters long ago. We used a dummy (resistive) load of 50, 75, 33, 100 and 25 ohms. 50 will give 1.0. 75 and 33 will give 1.5. Lastly 100 and 25 will show 2.0. The load should be resistive and use very short cables from the meter to the dummy load. We paralleled many carbon type 1Kohms to achieve the right resistance and power handling. regards, Reggie -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist