Chasing electrons...

To relax from the really serious challenges of life, I enjoy chasing around electrons in my free time.

www.simonsdialogs.com

Various stuff

• Kt100 Precision Thermometer
  Precision Pt100 thermometer, 0.001K resolution, 0.015K accuracy. Includes discussion of reference resistors and ADC linearity calibration. Quite a few of these are working in various research labs all around the world.
• Low distortion low-frequency oscillator
  Digitally tunable state variable oscillator, 10 Hz to 50 kHz.
• Low-power magnetic levitator
  Contribution to "Jugend forscht", build in 1991. Amazingly simple circuit. Still working perfectly fine.
• High-power magnetic levitator
  This is the high-power version of a magnetic levitator. Classic design controlled by light beam. Fully analog circit, includes position detector, PID regulator, 20 kHz PWM-controlled current regulator and safetly circuit. Easily holds 1 kg of massive iron suspend in air, several cm from the magnet core.
• Programming MAC address of ethernet adaptors
  At times, you need an ethernet adapter with a certain MAC address. Unfortunately, every adapter has its unique address, which is fine. Should you still wish to set your controller to a particular address, check out this document. Requires some hardware modification, but in the end, re-programming an EEPROM is not really big deal...

High-voltage stuff

• Van-de-Graaff generator
  Van-de-Graaff generator (German: Bandgenerator). Sphere diameter of about 30 cm, equals roughly 450 kV operation voltage.
• Marx generator (200 kV, 20 Joule)
  This is a pretty serious apparatus, nicely small and powerful. Don't show this thing to anyone scared of lightning, or thunder.
• Switchmode HV power supply (5 to 30 kV, 1 mA)
  Not too exciting by itself, but very useful. Getting this to work stable and reliably close to strong discharges was quite an effort. This power supply is used to drive Marx generators etc.
• Plasma speaker
  This apparatus produces sound. No, not just sparks - just let it play your favorite song. Audio signal fed from a MP3 player modulates coil current of a solid state HF transformer operated at 250 kHz resonace. Plasma burning at the top end of the secondary coil generates pressure waves - also known as sound.

High-frequency stuff

• DCF77 Frequency Reference
  10 MHz ovenized quartz oscillator, locked to the 77.5 kHz carrier frequency distributed by the DCF77 transmitter operated by PTB, Braunschweig, Germany.
• GPS Timing Receiver
  Experimenting with a GPS timing receiver, Motorola Oncore M12+.
• Simple Frequency Trippler
  10 Mhz to 30 MHz frequency trippler using PIN-Diode as step recovery diode.
• High-speed LED and laser diode light pulse generator
  Various attempts to produce 5 to 50 ns light pulses.
• 300 MHz light pulse detector
  Investiation of PIN photodiodes and amplifer circuits for the detection of fast-risetime light pulses.
• Tunnel diode pulser
  Generating wide bandwidth pulses using GaAs tunnel diode.
• Comb generator using ultrafast comparator
  Recently, ultrafast SiGe comparators with switching times below 50 ps became available at low cost. They give very fast transients for rise time measurements, but they are also useful as comb generators.
• Broadband noise generator
  Multiple designs for inexpensive noise generators have been described by various authors. For those who don't have access to a the very rare "noise diodes", here is an evaluation of Various active elements (Zener diodes, HF-transistor diodes) as noise generators.

Equipment gallery

Counters, Analyzers