Dear Sir,

Please refer to the attached Model 19 specs. The maximum driving voltage available is 2 volts, the DCR is 3 ohms, and it has 230 turns of wire on it. For a 20 amp input, the device will output 20/230 or 87 mA of current. The maximum available to the user would then be 2 – (0.87 X 3) = 1.74 VAC. To still stay in a reasonably accurate range, it is recommended to use 80% or less of the available output voltage, so for this app and CT, a burden resistor of 16 ohms would generate an ac voltage of 1.4 volts. This would give you about a 1% accurate part. You could improve on that slightly by running the CT at say 100 mV and then amplifying as you discuss. However, the amplifier chosen will add inaccuracies as well. We recommend high accuracy differential amplifiers like the OP07 products to produce the best results. Additionally, the model 19 was never designed to be a measurement style CT. A more appropriate choice is the CR8448-2500-N. Use of this part with an OP07 pre-amp would create a very accurate power transducer. I have attached the catalog page of our CR8400 Series for your review.