Difference current clamp TA234 vs TA189

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Difference current clamp TA234 vs TA189

Postby taho » Wed Jan 20, 2016 10:45 am

What are the technical parameters of the difference between TA234 and TA189 the current clamp , except for the size of gripper jaws?
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Re: Difference current clamp TA234 vs TA189

Postby PicoChris » Wed Jan 20, 2016 4:53 pm

The main difference between the two clamps is that the TA189 has a "closed loop" control system rather than the more common "open loop" system. This allows the clamp to have a higher bandwidth (over 100 kHz) and makes it less sensitive to noise. It is also less susceptible to thermal drift over time. This makes the clamp especially useful for looking at small fast changing currents.

The downside of these features is it can draw more current from the battery in use (reducing its life) and has a higher price due to the more complex design.

On the other hand the TA234 is a traditional open loop design but for the majority of automotive applications it should meet your requirements.
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Re: Difference current clamp TA234 vs TA189

Postby taho » Thu Jan 21, 2016 8:36 am

Thank you for the very useful information. And in the continuation of the question - then what is the difference between the current clamp TA234 and TA018 in 20A mode. Thank you.
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Re: Difference current clamp TA234 vs TA189

Postby PicoChris » Thu Jan 21, 2016 2:51 pm

The main differences between the TA018 and TA234 are the Jaw size and sensitivity to low currents. This gives the TA234 a definite edge, especially at the bottom of its current range. This can be significant when looking at very small currents with the scope bandwidth limit turned on. With these very small current the sensitivity of the TA018 is often not sensitive enough to give a sensible reading.

Please note that because of its increased sensitivity to low currents, with the TA234 you will need to have an appropriate low pass filter turned on to see the desired signal. (Try turning off the filters on the attached psdata file!)

The attached psdata file is a direct comparison of the two clamps (channels A and B) using a bench signal generator and a 47 ohm current limiting resistor to create the sample wave form. Channel C is measuring the voltage dropped across the current limiting resistor allowing us to calculate the actual current flowing through the clamps by ohms law (black channel).

From the file you can see that for this test the TA234 is still accurate whereas the TA018 finds the very low current challenging. Note that for larger currents such as those typically associated with pumps and injectors the TA018 is very good and the smaller jaws are often an advantage when fitting the clamp round tightly wrapped wires

I hope this helps


Chris
Attachments
current clamps low amps test demo.psdata
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