Welcome to my website danyk.cz dedicated to electronics

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-English version of this website is still under construction. Some articles are available in Czech only. They are in italic
My Youtube Channel - lots of new experiments and teardowns!
Resistor and inductor color band, capacitor and SMD resistor code online calculator


   high voltage danger High voltage:

2 meter arcs with 8 MOTs
3 phase arcs with 9 MOTs
Multi-mini High Voltage Transformer
Jacob's Ladder with 4 MOTs
6 MOTs two phase HV supply
HV supply with Integrated driver ignition coil
Adjustable stabilized switching high voltage supply 7-55kV
3-phase high voltage supply with 6 MOTs
Single MOT resonance arcs
The simplest power supply for Tesla coil with one MOT
Tesla Coil power supply with two MOTs (4200 Vac 0.7 A)
Two MOTs high voltage power supply (4200 Vac 0.9 A)
Stun gun (taser)
120kV Multiplier
80kV supply with TV transformer and multiplier
Mains voltage arcs
Kirlian photography
Plasma in a jar (fusor)
Marx generator 240 000 V
Jacob's ladder with 12kV 300W supply
40kV DC high voltage supply
Simple 60kV DC high voltage supply
Mains operated 20kV switched power supply
High frequency high voltage supply
Homemade plasma globe (ball)
Homemade plasma globe (ball) with EMI shield
Miniature high frequency high voltage supply

   TC - tesla coil:

Spark gap Tesla coil (SGTC):
Mini SGTC - Miniature spark gap Tesla coil
SGTC I. - Small Tesla coil
SGTC II. - Small Tesla coil II
SGTC III. - Middle Tesla coil
SGTC IV. - Bigger Tesla coil
SGTC V. - My biggest Tesla coil
Solid state Tesla coil (SSTC, ISSTC):
SSTC I. - Solid State Tesla Coil
SSTC II. - Solid State Tesla Coil with ion motor
SSTC III. - Transistor tesla coil with 50Hz/100Hz/DC operation and ion pendulum (propeller)

ISSTC I. - Single switch SSTC with interrupter
ISSTC II. - SSTC with interrupter
ISSTC III. - Simple low supply voltage ISSTC
Vacuum tube Tesla coil (VTTC):
Plasma flame - high current VTTC
Audio VTTC - Audio modulated vacuum tube tesla coil
VTTC I. - Big vacuum tube tesla coil with GU81
VTTC II. with RE025XA (4CX250B, SRL460)

   IGBT - high power supplies:

Switched 4kV 2000W supply with IGBT
Switched 40kV 1500W High voltage supply with IGBT and 2 LOPT's
IGBT halfbridge 20-200kHz with overload protection
High voltage Tesla coil supply with IGBT
Push-pull inverter with BUP213 IGBT

   Switch mode power supplies (SMPS):

Simplest switching power supply ever with TNY263 - TNY268
3.4V 2.5A supply with optocoupler
14.5V (8 - 18V) 0.4A supply with optocoupler
12V 5A switched power supply
12V and 90V switched power supply with UC3842
Simple non-regulated supply 2x 35V 350W for audio amplifier
Switched power supply 2x 35V 350W
Welding inverter up to 100A
Electronic halogen transformer
Switched current power supply for 1W - 5W LED diode
High power adjustable switching power supply (SMPS) 3-60V 40A
Single transistor switching supply without optocoupler
Very high current power supply (spot welder or car engine starting supply)

   Voltage converters:

12V / 325V 150W DC/DC converter
Universal DC / DC converter
12V / 15-21V car inverter for notebook
Multiphase synchronnous buck (step-down) converter
12V / 230V 50Hz square wave inverter with 555
12V / 230V 50Hz square wave inverter with IR2153
12V / 230V 50Hz modified sine wave inverter
Switching (transformerless) 12V / 230V 150W modified sine wave inverter
Single cell (1.2 or 1.5V) LED inverter (Joule thief)
12V fluorescent tube inverter 4 - 65W with high efficiency
Electronic ballast for fluorescent tubes 8 - 144W
CCFL inverter

   Induction heating:

Induction heating I.
Induction heating II.
Induction heating III. with IGBTs


Laser diodes from CD-RW drives can cut and burn!
Laser diode from CD-RW igniting matches
Powerful laser diodes from DVD-RW drive
1W 808nm infrared laser diodes
1W 445nm blue diode laser
Helium-neon (HeNe) lasers


1W 7MHz (40m) AM Transmitter
5W 7MHz (40m) AM Transmitter
5W 14MHz (20m) AM Transmitter
1.5W 88-108Mhz FM Transmitter
88-108 MHz FM covert listening device (bug)
Single transistor Miniature FM transmitter with VCO
Simple television transmitter

   Radio receivers:

Simple vacuum tube audion
Simple transistor audion


Vacuum tube preamplifier
Stereo vacuum tube audio amplifier
Stereo vacuum tube amplifier 2x 5W
Vacuum tube amplifier in class A
Simple audio amplifier 2x 100W RMS


Vacuum tube monitor with 8LO29M CRT
Vacuum tube monitor with 13LO3I CRT and sound

   Insect and animals:

Ultrasonic insect and rodent repellent
Powerful ultrasonic repeller of insects, rodents and martens with periodicly changing frequency
Electric insect zapper (killer)
Electric insect zapper (killer) II.
Electric fence


LED strobe light (stroboscope)
Stroboscope with oscillator
Simplified stroboscope with oscillator
Stroboscope with optoisolated external input
Various sound generators and sirens
Simple audio mixer

   PC accessories:

PC remote controlling with any remote controller
IrDA infraport for PC with TFDU4100 (motherboard connected)
Simple joystick / gamepad for PC

   Illegal (never try this at home):

Telephone wire tapping

   For household:

Infrared ON-OFF remote control
Remote control over power line
Load management tariff indicator
Simple intercom
Motion detector
Homemade solarium from mercury vapor street lamp
Light dimmer
Light bulb soft switching
Triac regulation of mains voltage
Simple electronic fridge thermostat

   Digital logic circuits:

Digital thermometer with LED / LCD display
Digital pulse counter
Neon lamp clock
Digital clock
Digital clock 2
Nixie clock without MCU
1970's TTL Nixie Clock


Atmel AVR for beginners - programming Light Snakes and Air display
Atmel AVR for beginners 2 - Interrupts and binary counter
Atmel AVR for beginners 3 - how to write the AVR
The simplest digital clock with AVR
The simplest LED alarm clock with AVR
Multifunctional real time clock with AVR
Multifunctional alarm clock with 2 displays
The simplest digital LCD clock with AVR
Digital LCD thermometer date clock with AVR
IN / OUT Nixie Thermometer
Nixie clock
Big Nixie Clock with Z566M / Z5660M / ZM1040
Numitron clock
DCF-77 radio controlled clock with VFD display
DCF-77 radio controlled LED clock
The simplest digital voltmeter with AVR
The simplest digital LCD voltmeter with AVR
Simple digital thermometer with AVR
Digital thermometer with MIN / MAX
Battery-powered thermometer with MIN / MAX and adjustable brightness
Solar LED thermometer new
Dual AVR Thermometer (internal + external / laboratory) with MIN / MAX
Wireless digital thermometer
Simple 4-channel ON-OFF remote control
4 command IR remote control
Simple 16-channel ON-OFF remote control
Combined 10-channel remote control
Radio-frequency ON-OFF remote control with 4 channels
Digital thermostat with AVR
Simple AVR digital scope
The simplest frequency meter (counter) up to 10 MHz
6 digit 10 MHz frequency meter (counter) II
10 MHz frequency meter (counter) III. with 0,000 001 Hz resolution
Digital Radiometer - Dosimeter
The simplest LED sound level indicator
Sound level indicator with 2x 20 LED and peak indicator
The simplest digital tachometer
Simple weather station (thermometer + hygrometer + barometer)
Simple code lock
Rechargeable battery capacity meter (analyzer)
Rechargeable battery capacity meter (analyzer) 2 new
Transformer / inductor tester (ring tester)
Transformer, inductor and capacitor in-circuit ring tester

   Measuring ant testing:

Vacuum tube scope
Simple tester of transistors and other components
ESR meter - Electrolytic capacitor tester
High frequency currents measuring - HF probe for ampermeter
Electronic resistor - variable dummy load for power supplies
High voltage measuring - (kilo)Voltmeter up to 80kV
High voltage conductivity tester
ATX PC power supply tester
Simple inductance meter
GM counter - radioactivity meter
Wattmeter (simple AC power meter)
Pocket radioactivity detector
Color LED temperature indicator
Car battery voltage LED indicator
Test wall socket with current limiting
Analog and digital electronic thermometer with LM35
Simple digital frequency meter
Hall effect sensor - magnetic field detector
1.25-5.5V 0-200mA bench power supply
1.25-15V 0-350mA bench power supply


simpe Li-Ion and Li-Pol cell charger
NiMH and NiCd Charger with automatic discharge
Button cell (watch battery) charger
Switching charger for car batteries, sealed lead-acid, VRLA batteries and gel batteries


Exploding wires - 2600J energy capacitor bank
Electronic fuse up to 400V
Delay switch and inrush current limiter
LED light bulb
Infrared photos and night vision
Build your own night vision from an ordinary camera
450J Coil Gun
Big coil gun 2500J (not finished yet)
Electric shock device 1998
ELEKTROX 1 - two-channel electromassage (electrostimulation) device
Electromagnetic levitation device
Various LED and neon lamp flashing circuits
Oscilloscope from a TV - TV shows a music!
LED 555 police flasher
Single button ON-OFF toggle with discrete transistors
Deep discharge battery protection, undervoltage protection
Perpetuum mobile - "free" energy generator from a candle :)
PC Fan with color LED effect


Operating magnetron without an oven (building homemade microwave oven)
Microwave magnetron in free air - measuring spacial distribution and other experiments
Magnetrons - Microwave plasma flame and other dangerous experiments
Magnetron and a plasma flame at 200% power - 1400W, 100Hz
Audio modulated microwave magnetron
X-ray source with DY-87 vacuum tube diode
X-ray with 6VS-1 tube (making x-rays of semiconductors using CCD)
Fluoroscopic X-ray pictures
Fluoroscopic X-rays II.
High pressure sodium lamp (HPS) producing X-rays
Fluoroscopic X-ray with 6VS-1 and X-ray cassette
Homemade X-ray photography
Homemade X-ray photography II.


How to modify an AT / ATX computer power supply to a 3-15V bench power supply
Modification of 100V amplifier Tesla AUJ 635 to a classic amp (4ohm)
Modernisation of the portable fluorescent lamp PZS-01


How to make MicroSIM from SIM
How to build MMC
How to build TC capacitor of linoleum and aluminium foil
Internal schematics and connection of IHVTs (LOPTs)
MOT as a high power low voltage supply
Switchning power supplies and inverters I. - Overview of topologies of switchning power supplies
Switchning power supplies and inverters II. - Overview of topologies of inverters
Switchning power supplies and inverters III. - Transistors protection


Online physical units converter (incl. metric - customary - imperial)
Online calculator for electronics
Online calculator for electronics - new
Resistor color band and capacitor code online calculator
RLC circuit graphic simulator
Testing patterns for monitors
Useful formulas you won't find in textbooks
How to photograph macro using mobile phone :)
Table of my MOT's (make idea of their parameters)
Reverse engineered schematics
Dots in transformer windings - What they mean
AT and ATX PC computer supplies schematics
Czech CKD semiconductors datasheet catalog (SCR, GTO, IGCT, diodes, modules, IGBT, ...)
Online RGB and hex # color tester


Some of my videos for download
My Youtube Channel
My Youtube Channel - in English
Interesting videos from other users


My virtual technical museum
Curiosities from the world of electronics
Curiosities from the world of computers
"Supersafe" line splitter - do you like electric shocks ?
Chicken servicemen in action
Schematuum mobile - schematic shits that could never work :)
Dark side of Windows Vista or Why not to be fooled WOW effect
Trust SP-3150 sound system - what's inside
Radiation background measurement
Radioactive household items
EU light-bulb ban - but you can still buy them. How is this possible?
Mercury thermometer ban - what is the best replacement?
Beware of fake NiMH rechargeable batteries
Test of cheap Li-Ion 18650 cells - beware of fakes
Gopro Hero4 Silver review
Nixie tubes
Electro Antiperspirant - how does this machine work


Free navigation in your cell phone   (Part 2)   (Part 3)


About me
About this site
FAQ - Frequently asked questions
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Established: 2002 | Last update: 24. IV. 2024 | 1024 x 768 | danyk(at)centrum(dot)cz