33622A used to measure Capacitors and Inductors - Curve method

18 May 2014

With the 33622A Arbitrary Waveform generator I was sent for review from Element 14, I have discovered it is possible to use it for some basic component measurements with surprising accuracy

this is a link back to the primary review http://www.element14.com/community/roadTestReviews/1744

In this blog I will show you how to use basic techniques to derive the value of unknown capacitors and Inductors

All you need is a fast pulse (Compliments of the 33622A), an oscilloscope and a known value Resistor set (1K, 10K, 100K and greater), really any values will do, you just need to know the real value.

The test schematics:

So without further ado, lets measure some caps

33622A Setup and sample scope display

Initial Setup for capacitor measurement and sample displays for "Scope Probe" and then C3 with a 10K resistor

The capacitor tests being performed using the 33622A as a high accuracy and quality square wave generator

Setup for Inductor measurement, Un-Expanded ringing view, Partly expanded then expanded view in order to measure ringing frequency

The Inductor Tests being performed using the 33622A as a quality square wave generator

Now that all the measuring is completed, here is the Math

EXCEL Spreadsheet Math

	R in Ohms	time in Seconds	C Calc in Farads	C DMM Measured	Marked on device
C0	100800	1.56E-06	1.54762E-11	8.43E-10
C1	100800	1.17E-03	1.16071E-08	1.10E-08	10nF
C1	9960	1.17E-04	1.1747E-08	1.10E-08	10nF
C2	9960	9.80E-04	9.83936E-08	9.73E-08	100nF
C3	1001	5.50E-03	5.49451E-06	5.54E-06	4.7uF
C4	1001	1.11E+00	0.001108891	1.01E-03	1000uF

	f	w: (2PIF)^2	H: (W * C)	uH
L1	132900	6.97284E+11	1.46E-05	14.58
L2	22620	20199700856	5.03E-04	503.14
L3	29070	33361825025	3.05E-04	304.64
L4	20000	15791367042	6.44E-04	643.60

Attachments:

Inductors And Capacitors.xlsx

Parents

DAB over 10 years ago

Hi Peter,

Good post.
This is one of those exercises I wanted to do, but never found time to do it.
We just take the stated values of components at face value and we just assume that they are within the tolerance range.

DAB
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peteroakes over 10 years ago in reply to DAB

What I find more interesting is that people assume their test measurement equipment have no affect on the measurement forgetting the 1Mohm or 15pF input loads it applies thereby distorting the measurements in many cases
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peteroakes over 10 years ago in reply to DAB

What I find more interesting is that people assume their test measurement equipment have no affect on the measurement forgetting the 1Mohm or 15pF input loads it applies thereby distorting the measurements in many cases
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