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Impedance of ERB24 at 400 kHz



I would like to run a 3-volt 400 kHz sinusoidal signal through the USB-ERB24 relays.  I can’t find specs related to impedances of the relays for higher frequencies, or any information about frequency limits.

Would there be any problems with us using this device for this purpose? 

Is there any impedance vs. frequency data for this device?

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Posted (edited)

@JRys For higher-frequency signals, any capacitance or inductance in the components or the circuit board changes impedance more as you go higher in frequency.

If you have a way of measuring capacitance, measure from one ERB24 relay input or output to other relay connections around it and also to ground.  If you have a way of measuring inductance, connect to the common and normally closed terminals of a relay and read it.

If you have access to a network analyzer, it can sweep through a range of frequencies as it detects the impedance of the circuit it is connected to.  If you don't, you can manually connect a function/signal generator so it sends a 400 kHz signal through a relay on the ERB24 in series with a resistor.  Then you can see if there is any signal voltage across the ERB24 and compare it to the signal voltage across the resistor.  Then calculate the impedance of the ERB24 at that frequency.  There may be some phase shift which can complicate the calculations.  That's why a network analyzer is the far easier way to go.  Or, you could send noise through this circuit and see how it is affected by using a spectrum analyzer on the input vs. the output of the ERB24.

Edited by BradM
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