3/18/01 - Just got a Fluke 105B ScopeMeter from E-Bay.  This is a portable, two channel, 100 MHz, digital storage oscilloscope and multimeter.  It came with an optically isolated, RS-232 adapter and Windows 95 software .  I spent the weekend learning how to use it.  The following screen shots show my results so far.

This picture shows the output from a small Variac I have, set to ~50 volts AC.

This picture shows the drive side of an old, solid state HV supply that I built in high school (about 25 years ago).  A two transistor oscillator drives the input of a 12 volt ignition coil.  With twelve volts in to the oscillator, the coil primary is receiving  a 30 volt pulse about every millisecond.

Here is the output waveform display from the ignition coil.  This was taken using my 40KV, 1000:1 probe coupled to the 105B with its normal 10:1 probe.  The time between peaks is ~1.75 milliseconds, giving a primary frequency of 570 Hz.  There is also a secondary frequency of ~7 KHz apparent as a ringing after the main peak.  Peak to peak  is ~1500 volts.  (The input voltage was lower for this test, I'm still a little nervous about putting KV's into my new toy.)

This screen shot was made by positioning the tip of the 40KV probe about a quarter of an inch from the spinning bottle of my Bill Beaty style electrostatic motor.  You can see the potential swing between ~4 and 10 KV as the aluminum sectors on the bottle turn past the probe.  Since there are three sectors, the frequency of 26 Hertz corresponds to 520 RPM.

This one is from my other electrostatic motor.  Here the potential is spiking from ~6 to 22 KV as the two points pass the probe tip.  The frequency gives the rotation rate as 498 RPM.  (Both motors were connected to ~30 KV.)

Next, I need to get some 50 W shielded cable so I can hook up my 500KV probe, and some wire mesh to build a Faraday cage for the 'scope.

10/20/01:  I've modified my 500KV probe with a BNC bulkhead jack so that it can accept 50 W shielded cable.  I bought two 10' and one 1' BNC terminated cables and two jack to jack connectors so that I can connect them all together.  I also made two heavy ground cables from 6 AWG welding cable and large copper battery clips.  In use, the 1' long cable is connected to the oscilloscope and the ground clips are conncted to the jack to jack BNC connector that connects the 1' cable the long cable or cables.  I also bought a BNC to banana jack adapter, so that I can still use the modified probe with a digital multimeter.
 

This picture shows the grounding method that I described above.

In order to keep page sizes reasonable, I will start new pages for additional measurements.

Marx generator measurements.

Tesla coil measurements.
 
 

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