Selfrunning cold electricity circuit from Dr.Stiffler

[amigo]

Did you buy this by gun point? These gen's are $1,495 new.

Close by, it was some liquidation where they had it, was not tested just powered up in the picture so I took a chance. Now at the closer inspection it seems that the function generator output is bad since I get nothing on the 1st BNC to the right - only get the pulse/square out (2nd BNC from the right) and the rest of the SYNC outs. Luckily, I found a full manual with the service schematics so hopefully I can figure it out.

There was one more seller with this model of Wavetek who offered it to me for $150. I am PM-ing you the details since you were interested, otherwise if you are not just post the details here.

[amigo]

I cannot emphasize how important Ebay is for test equipment.  I live and die with equipment off there.  Most of my test equipment I get for less than 1/10 of what it cost new!  Of course you have to read the fine print and know what you are doing but for us old timers, what a deal!

Amen to that!

[MarkSnoswell]

Preliminary note only:

Results with ferrite antenna transformer, 2 IN4148 diodes and LED. All tests done with "open air" circuit (no breadboard -- no capacitive metal anywhere close, no earth connections).

No problems getting LED to light.

Coupling from signal generator::
Presence (or absence) of series capacitor (470pf) or inductor 2,2uH in signal generator supply line make no difference to operation.

Diode type used for Avramenko Rectifier (AR)::
Testing several types of diodes suggests that diode capacitance needs to be low. Circuit worked poorly with ultra high speed power diodes (medium junction capacitance) and did not work with 200V schottkey (highest junction capacitance). These results suggest that low serial capacitance is required in the load for optimal output.

Capacitive load tests::
Placing series capacitance in the load dramatically reduces the output while placing parallel capacitance enhances the output. Parallel capacitance on the load does not effect the resonance frequency.  Capacitance to ground on the load side enhances the output although the resonance is shifted to a lower frequency - as you would expect.

Load diode orientation::
Same operation with load LED in either orientation. Similar output power with two LED?s in parallel. No output with two LEDs parallel in opposing orientation. It appears that a polarized capacitive load is required for operation.

Preliminary finding on capacitive load::
Parallel capacitance is required on the load for function. This can be provided by capacitive coupling to ground or across the AV plug directly or via the junction capacitance of a load diode.

Square vs sine wave drive::
Both sine and square waves work just as well at the fundamental resonance. Square wave works better at sub-harmonic frequencies.

Principal resonances with no load to ground::
The fundamental resonance with no capacitive loading to ground (15ph scope probes) on the load was 12Mhz. Sub harmonics that give significant output are the 1/3 and 1/4. The principal frequency of 12Mhz gives the greatest output.

Principal resonances with load to ground::
With symmetrical 15pf load to ground on the output the principal resonance was reduced to 9.4 Mhz. Both 1/3 and 1/4 sub harmonics were present. The 1/4 frequency (2.34Mhz) now give the highest output. The waveform of the 2.34Mhz resonance is a rounded triangle wave indicating 3rd harmonic (almost a text book example of triangle wave synthesis with first and third harmonic components). The principal resonance was observed directly and in ringing on square wave drive at lower frequencies. Measurements of the frequency on the ringing confirmed the presence of a single principal resonant mode.

Load waveforms::
At all times the signals on the load were in phase but had a DC offset.

Single and double ended drive::
The circuit works similarly with single or double ended drive to the primary.

All tests were done with a HP33120A signal generator (10 Vp-p output). Measurements were made with Tektronix TAS 475 scope (100MHz 4 trace). Unless indicated otherwise all scope measurements were done with 10X scope probes with tips held close to leads to eliminate load effects on the measured circuit.

The next tests will look at antenna transformer ? number and direction of turns in the primary and secondary and alternate cores. I will also measure the Q of the principal resonance. Load tests will look at inductive influences.

Cheers

mark.

[hoptoad]

I don't know whether to be alarmed or just disappointed, but I tried to re-view Cold Electricity Part 9, and could no longer find it anywhere!!??



KneeDeep from the Toad who Hops

[hartiberlin]

Hi Mark,
many thanks for the tests.
Yes around 12 Mhz I also get now the best light output, but still better when the core is removed.
As I only have a 10 Mhz scope the measurements have to be done with the horizontal 5x zoom factor, as my deflection time only goes to 0.5 usec.
The new IC 40106 is now much better and I will later post pictures and a new video.
But I still think I dont have the right cores, cause I dont get any amplification...