The World Leader in Electromagnetic Physics. Capacitor Anomaly

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1 By Robert J Distinti B.S. EE 46 Rutland Ave. Fairfield Ct (203) Capacitor Anomaly Absttractt This paper discloses a phenomenon associated with capacitors which may cause problems when employing microvolt sensitive instruments. This paper is presented in 3 sections 1) Demonstration of the anomaly 2) Possible explanations 3) Techniques to mitigate Copyright 2003 Robert J Distinti. Page 1 of 11

2 1 THE PHENOMENON BASIC DESCRIPTION POSSIBLE CAUSES SOLUTIONS Opposing Capacitors Drain Resistor Use polypropylene caps MORE INFORMATION REGARDING THE ANOMALY Variation in Bounce Back CONCLUSION Copyright 2003 Robert J Distinti. Page 2 of 11

1 The Phenomenon 1.1 Basic Description Capacitors produce energy in their own right. This energy is very small and may be thermal electric in origin.

3 1 The Phenomenon 1.1 Basic Description Capacitors produce energy in their own right. This energy is very small and may be thermal electric in origin. This energy is observed by placing a DVM across the terminals of a capacitor as shown in the following diagram. At first, we thought that the energy built up across the capacitor was a ratcheting effect caused by the interaction of small stray ac signals and the input junction of the measuring device. If this were the case, then reversing the leads should affect the direction of charge buildup across the capacitor; this is tested in the following experiment. Copyright 2003 Robert J Distinti. Page 3 of 11

4 The next photo shows a capacitor connected to a scope through a DVMx1000. The scope is set to 10 seconds per division (like a strip recorder) and the vertical scale is 1 Volt (which correlates to 1 millivolt per division). In the first second of the experiment, the leads of the capacitor are shorted causing the flat line seen in the first division. When the short is removed, the capacitor charges as shown in divisions 2 to 4 on the screen. Then the leads are reversed (the vertical solid bar is the period when the leads are being reversed). The last section of the trace (divisions 5 to 10) shows that the buildup of charge across the capacitor continues in the same direction (relative to the capacitor). Since the capacitor continues to charge in the same direction regardless of the connection to the amplifier, the energy does not come from the amplifier. In fact the DVMx1000 has a leakage current rated less than 50 pico-amps which is not enough to cause the charge buildup at the above rate (the capacitor is 100uf). Random tests of capacitors from our parts inventory show terminal voltages as much as 50 millivolts. Copyright 2003 Robert J Distinti. Page 4 of 11

5 Other tests show that the charge buildup is increased by warming the capacitor. This suggests that the charge is separated through a thermal electric type (Seebeck) effect. 1.2 Possible causes Since the energy seems to be increased by warming the capacitor, it is possible that the energy is produced by thermal electric effects. Another possibility is that the capacitor produces electrostatic charge in the same manner as an electrophorus. An electrophorus is the electrostatic equivalent of a magnet. Unlike a battery, an electrophorus can not be drained of its ability to generate electrostatic charge (This is not first hand knowledge on our part. See the book Homemade Lightning by R.A Ford for a recipe and operation of an electrophorus. There should be a link for the above book where you found this paper). At this point we do not consider this phenomenon of interest except that it has plagued our other experiments by adding voltage offsets and instability that we could not account for. Using the techniques developed in the next section will allow you to mitigate these effects to improve experimental accuracy. 1.3 Solutions Opposiing Capaciittors Placing two capacitors in parallel opposing or in series opposing enables the effect to be cancelled. It is important that both capacitors be measured to ensure they produce similar energy such that the cancellation is maximal. Copyright 2003 Robert J Distinti. Page 5 of 11

6 WARNING: When using electrolytic capacitors, this technique is only for making measurement of small voltages (under 0.1 volt) since reversing the polarity of voltage applied to an electrolytic capacitor can cause it to leak or explode Draiin Resiisttor By adding a resistance in parallel enables some or all of the excess energy to be drained away. Copyright 2003 Robert J Distinti. Page 6 of 11

The above photo shows the steady state reading (400uV) of a 100uf capacitor in parallel with a 1Mohm resistor. This means that the capacitor is capable of producing 400pA at 400uV at room temperature.

7 The above photo shows the steady state reading (400uV) of a 100uf capacitor in parallel with a 1Mohm resistor. This means that the capacitor is capable of producing 400pA at 400uV at room temperature. With a 100K resistor, the output drops correspondingly to about 40uV. The problem with the drain resistor is that it may load down your experiment unnecessarily Use pollypropyllene caps We tested many types of capacitors for this effect. All of the following types exhibited the anomaly: 1) Monolithic 2) Electrolytic (aluminum) 3) Bi-polar Electrolytic 4) Tantalum Copyright 2003 Robert J Distinti. Page 7 of 11

8 The following types did not seem to experience the phenomenon 1) Polypropylene 2) Ceramic disk Note: You should perform your own tests to find suitable capacitors since we only tested a few of each type. Most of the capacitors tested were from our R&D inventory which may be as old as ten years. We did not test surface mount varieties. We are not sure if this phenomenon is dependent upon construction, age, manufacture or the environment in which the caps are stored. It may very well be the case that this phenomenon affects capacitor from the same batch differently. The following scope trace is the test performed on a 0.33uF polypropylene capacitor. Because the input is though a DVMx1000, we must divide the scope readings by This means that the charge rate is approximately 100uV per second. For the 50pA rated maximum leakage of the DVMx1000 across the 0.33uF capacitor, we should expect 50e-12/3.3e-7 = 150uV/sec in charge buildup. Since the charge buildup is about 100uV per second then this buildup is clearly capable of being caused by amplifier leakage. We demonstrate that this charge buildup is the amplifier by reversing the leads on the capacitor. Divisions 7 to 10 show that the direction of charging follows the instrument, not the capacitor. This clearly means that the charging error is from the amplifier and not the capacitor. Copyright 2003 Robert J Distinti. Page 8 of 11

9 Figure 1-1: Polypropylene Capacitor Test Note: at the 6.2 second mark the leads were inadvertently shorted, that is why the trace resets to zero. Had the leads not been shorted, the trace would have continued from the -800uV mark (which is shown leading out of the changeover region) toward the positive direction. 1.4 More information regarding the anomaly Variiattiion iin Bounce Back After being shorted, the phenomenon does not seem to bounce back as strong. The following screen shot shows a monolithic capacitor which is repeatedly shorted. Each time the charging rate seems to diminish. Copyright 2003 Robert J Distinti. Page 9 of 11

11 2 Conclusion The discovery of this phenomenon has enabled us to resolve some outstanding issues in New Electromagnetism research. We hope this information is of use to you as well. Copyright 2003 Robert J Distinti. Page 11 of 11

Maxwell s Omission #1

Absttractt: :: By Robert J Distinti B.S. EE 46 Rutland Ave. Fairfield Ct 06825. (203) 331-9696 Maxwell s Omission #1 Maxwell went to great length to derive point equations from the classical models that