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The coils we are using have what appears to be an oversized coil form. The form has gaps that allow the coil to freely move about the core. This is a simple fix using a wood toothpick cut with a Xacto knife to the size to wedge into the space areas. Fig: 1
Here the coil is shown with the two small wood wedges. Center the winding and slip in the wedges for a snug fit, do not force the wood. Place two small drops of rubber cement on each end of the paper coil form. This will work with the wood wedges to hold the coil in place. Be careful not to get the glue on the coil itself and do not use to much glue as it will interfere with the addition of the primary winding. Fig: 2
Finding the coils self-resonant frequency. Fig: 3
A 50-ohm resistor (matching generator impedance) is placed in the ground return lead of the coil under test. Channel two (2) scope input is placed here and channel one (1) is placed at the generator input to the coil. The generator input is held at a constant input voltage as measured at the scope (1) input while the generator scans through its range. Fig: 4
Above is a scope shot of the low frequency side of the coil resonance. The generator is swept with constant input until the lowest voltage is detected across the 50-ohm load. The following shows the high frequency side of the coil self-resonance frequency. Fig: 5
The following is the scope display of a typical coil self-resonance point. It is easily seen that the coils impedance is the highest at this frequency. Fig: 6
Using the measurement method as described above the follow are the results of one of our typical coils. Self-resonant frequency; fsr =
7,061,800 Hz This falls within the range of the measurements found in the initial work and covered at http://67.76.235.52/CE4.asp That data was;
Before winding the Primary layer over the top of the Secondary, determine the winding direction of the Secondary Coil. Mark the core with a pencil or marker pen so that it will be visible during the winding procedure. Place two layers of Electrical Tape, Plastic not Cloth over the top and in the center of the Secondary. Be careful not to pull the tape to tight as it will distort and damage the fine wire of the Secondary. Fig: 7
The same test was run on a typical coil and core once the primary was wound over the top of the secondary. The free ends of the new Primary can be secured with plastic electrical tape. Usage of small wire ties is not recommended, as they do not secure the wire firmly enough. Of course if the coils should change, so do your operational points. Fig: 8
The effect of the added primary can be seen in the following measurements. Self-resonant frequency; fsr = 5,597,529
Hz Fig: 9
Figure (9) shows the configuration for testing the affect of changing values of C1, two different values were used, 400pF and 330pF. The results of the scan are shown in the following. C1=400pF - L1=800nH Reference Null; fsr = 4,758,184 Hz C1=330pF - L1=800nH Reference Null; fsr = 4,787,230 Hz Fig: 10
When the series combination of C1, L1 is used to feed the power coil, specific frequencies are found where amplification occurs. The specific frequencies found were; 15,163,935, 15,185,340 and 18,612,282. The following chart indicates the observed amplification frequencies. Fig: 11
In the following circuit the frequency response of the secondary was measured using both C1=400pF and C1=330pF. Fig: 12
C1=400pF - L1=800nH Reference Null; fsr = 4,451,374 Hz C1=330pF - L1=800nH Reference Null; fsr = 4,481,603 Hz
The following chart plots the power points of the primary and secomdary combined. Fig: 13
The amplification peaks occur at; 11,963,991 MHz C1=330pF testing
secondary From looking at the above power peaks we can assume that there are three distinct frequencies where amplification takes place and they are; '12,0xx,xxx', 15,1xx,xxx', '18,6xx,xxx'. The following tables show the calculated Impedances for three different capacitor values of C1 with L1 of 800nH. In the calculations the resistance value of 1-ohm was used. Tbl: 1
Tbl: 2
Tbl: 3
When the L1 value od 2.2mH used with capacitors of 400pF, 330pF and 100pF the following Impedances were calculated. Tbl: 4
Tbl: 5
Tbl: 6
Measuring Input Power Fig: 14
Resistor Rg is selected to match the output impedance of the signal generator, in most case this will be 50 or 600 ohms. In RF generators it is usually 50 ohms. With an RF probe and DMM or DVM, measure the RF voltage Vg (to ground). In a like manner measure RF at input to Cin , (to ground). Measure the RF voltage drop Vd across Rg. Now do the calculations Va = Vg - Vin should be equal to Vd or within 1-2% Current into the circuit Iin = Vd / Rg Power in Pin = Vin x Iin to the circuit, total power including P(Rg) = Vg x Iin Circuit input impedance Zin = Vin / Iin
Various Output Power Measurement Setups Fig: 15
The preceding test was put together to be a quick and simple check. It may have failed because a thermal enclosure was not used. The idea was that a Black Al plate coated with a fine carbon powder should absorb the photons emitted by the LEDS. It was not expected that this would be an accurate indicator, but it was expected to show a small increase in the Black plates temperature. In this test, that increase was not seen. Therefore it was necessary to try something a little more sophisticated. A thermal bottle large enough to hold one of the evaluation circuit boards was secured and insulated. A large 2-watt carbon resistor was placed in the container and the voltage and current supplied to it were selected to match what the circuit board would draw. The temperature was monitored at four-minute intervals for one hour. Next the container was stabilized to ambient and the circuit board was placed in the container. The temperature was again allowed to stabilize before the test began. Again the temperatures were monitored at four-minute intervals for a period of one hour. The following image show how the test was performed. Fig: 16
Power Supply Decoupling Because the SEC circuits work at very high frequency and high impedance, it is necessary to decouple the power supply from the circuit so that you do not introduce feedback paths or ground loops. The following two photos show a decoupling unit that I build up and use with the circuits. The circuit included 10 x 10-ohm resistors in parallel and in series with the ground return and providing a way to measure supply current.
Measurement Instrument Decoupling Because of the high-localized RF levels in and around a SEC circuit, measurement of circuit voltages and waveforms are far from straight forward. As with the required power supply decoupling, most non-RF measurements will require some method to decouple or filter out the localized RF. In most cases a filter build from capacitors and inductors will suffice, although care must be used in the filter components used and how they are used in the filter. The following images show a filter circuit I use for DC measurement within SEC circuits. Fig: RFF01
Shown in Fig: RFF01 is a common RF filter that can be used to measure and monitor DC voltages in the AV Plug portion of a SEC circuit. This image shows the filter connected on the AV Plug output monitoring the charge/discharge and timing of a storage capacitor into an incandescent bulb, switched by a Sidac. Fig: RFF02
The preceding image (Fig: RFF02) shows a blowup of the RF filter I use in many measurements within development SEC circuits. Fig: RFF03 The schmatic of the filter circuit shown in (Fig: RFF01 and RFF02).
Measurement Pitfalls. 1) It is an absolute requirement that all DVM, DMM, VOM or other meter leads be as short as possible. Even with a good RF filter, the usage of long test leads is counter productive and 99% of the time will result in erroneous readings. 2) All instruments used to obtain measurements from the AV Plug should be self powered (battery) and not connected in any way to a power grid. Connection of the AV Plug to an Earth Ground or any power system that is at some point returned to an Earth Ground will detune the AV Plug to where it no longer will interface with the Spatial Lattice. 3) Handheld (battery powered) oscilloscopes are the only method that may work for observing the waveforms present on the Input and Output of a Spatial Interfaced AV Plug. Using a grid-powered scope, even with differential or isolation probes, will disrupt a working Spatial Interface. |
