Q: We need a source of high frequency current to obtain the frequency response of instrumental CT (transform ratio is 1/4000, 1 or 5 A nominal current), which used in intellectual electronic device.
I would like to know is suitable your device for this purpose and how to connect. Maybe you have devices with higher output current?
A: The bandwidth for the measurement isn't stated, but the answer is probably. The setup would be much like in our measuring inductors with DC Bias, but using a pair of current probes. The J2121A has a built in hall monitor with a 1MHz 3dB bandwidth. That might be simple, but...
Set an external bias current using the bench power supply powering the J2120A or J2121A.
Modulate the line injector with the FRA source signal.
Measure the ratio of the current transducer to a known flat current sense signal.
The known current signal can be an external current probe or the Hall monitor in the J2121A (for <1MHz).
This is how we measure current transducers here.
Q: Thanks for the answer. I would like to clarify my question.
We want to use J2120A as a source of high frequency current, which generates current in frequency range 10 Hz -10 MHz to obtain the frequency response of instrumental CT. We will use Oscilloscope and current sensors that are in our enterprise.
Is it possible to build such a test circuit using the J2120A? How to connect J2120A in this case?
A: Your connections are correct, though since the J2120A can only source current, it will only work with DC Bias. The modulation voltage can be up to about 1Vrms, depending on operating current.
Q: What is the function of the BNC input and whether we need to use the BNC input in our test circuit?
A: The input power is heavily filtered and conditioned before being sent to the output. There is an open loop MOSFET buffer in the output (for stability and minimum output impedance), but the output would just be DC. The modulation is added to the DC via the BNC connector. So, no, you don’t need BNC on your board. The OUTPUT banana jacks will include the DC+AC signal.
See the datasheet or J2120A web page for the voltage drop and output impedance data vs output current:
Q: After re-reading the documentation, I had the following questions:
1. Does the signal supplied to the "OSC" input determine the signal at the output "out"?
2. Is J2120A a voltage source, not a current source?
2. Yes, it is a voltage source.
Be sure to see the output resistance vs DC current curves in the datasheet. The voltage source is connected through this resistance plus the interconnecting cables.