Electronics circuit designed by Tomi Engdahl
Nothing on these pages is for sale, and I will not build these or sell kits or parts to you.
I have designed those circuits for my own hobby use and are presented here as is. I have tested the circuits presented in this page but there is no guarantee that the circuit descriptions and diagrams are entirely correct. I will try to correct all the error in the circuit diagrams when I or somebody else find those.
Please note that I do not supply electronic components or kits for building any of the projects featured. I do not have list which would be the best source to get the needed components in various countries. I strongly advise readers to check that all parts are available before commencing any project.
Index
These pages are not an advertisement for a commercial product. I don't have components, circuit boards or kits for sale for those projects (if someone has interrest in turning some of those circuits to kits and sell then contact me for more deltails). The circuits are mostly build on some quite small set of basic electronics components which I basically use when I need to build something which does not need any very special components. I will try to answer your questions if they are relevant but I don't have too much free time nowadays.
Disclaimer
This information and the circuits are provided as is without any express or implied warranties. While every effort has been taken to ensure the accuracy of the information contained in this text, the authors/maintainers/contributors assume no responsibility for errors or omissions, or for damages resulting from the use of the information contained herein.
I disclaim everything. The contents of the articles below might be totally inaccurate, inappropriate, or misguided. There is no guarantee as to the suitability of said circuits and information for any purpose whatsoever other than as a self-training aid. I.E. If it blows your equipments, trashes your hard disc, wipes your backup, burns your building down or just plain don't work, IT ISN'T MY FAULT. In the event of judicial ruling to the contrary, any liability shall be limited to the sum charged on you by us for the aforementioned document or nothing, whichever is the lower.
I will not be held responsible for any damages or costs which might occur as a result of my advice or designs. Not any of my designs are allowed to be used for commercial purposes without my written authorization .
Audio circuits
- Audio amplifier output relay delay
- Audio line isolator
- Dynamic microphone to electret microphone input
- Electret microphone powering circuits
- Line level signal to microphone input adapter
- Simple circuit to connect telephone equipment to audio mixer
- Simple line mixer
- Simple two line output combiner
- Simple microphone preamplifier
- Speaker signals to line level inputs
- Use amplifier phono input as line level input - inverse RIAA filter
Video circuits
- S-video to composite video adapter
- TV/Radio antenna cable galvanic isolator
- VGA to PAL and NTSC converter - converts RGB to S-video and composite video signals
Computer circuits
- Analogue to digital converter for PC serial port
- Get power out of PC RS-232 port
- RS-232 surge protection
- Digital to analogue converters for PC parallel port
- Get power out of PC parallel port
- Parallel port interfacing made easy
- Simple printer emulator adapter
- Connect two CD-ROM drives to one soundcard
- Headphone driving circuit for soundcards
- Simple MIDI tester
- Sound Blaster Microphone Preamplifier
- VGA converter for video projectors and fixed frequency monitors
- VGA to TV converter
- VGA to PAL and NTSC converter - converts RGB to S-video and composite video signals
Serial port
Parallel port
Soundcards
Video
Misc
Data communication circuits
- Experimental laser data link
- Simple IR transmitter circuit
- Simple RS-232 serial port buffer circuit
- RS-232 serial line surge protectors
Light effects and controllers
- 12V stroboscope
- Analogue light controlling desk
- Four channel dimmer rack
- Mini pocket stroboscope
- Simple light bulb flasher
- Strobo controller
- Strobo controlling with PC using RS-232 port
- Stroboscope trigger circuits
Telephone circuits
Power supplies
Measuring equipments
Other circuits
Information on getting the components
The circuits above are mainly designed using components which are easily available types in Europe. When I start to design circuits I usually pic the components from my basic electronics components list.
If you have problems on finding components to the electronics project on this document collection then don't e-mail me how to find those components. I know where to buy the components in Helsinki in Finland. If you happen to live in some other country or city then I don't know what are good places for you toget those components. Please consult my list of electronics component dealers to find one which can supply you the components.
If you happen to live in USA, you can't easlity get exactly the same components, but you can find suitable replacements for most of the components from Radio Shack using my European component types to Radio Shack types table. If you have problems in reading the component value markings then read the component markings description document.
Electronics documents written by Tomi Engdahl
- 3D glasses and other 3D display devices
- CD-ROM audio connectors
- Connecting computer soundcard to telephone line
- Dangers and problems of ungrounded PC
- Generating DTMF tones using soundcard
- How lightpen works
- How multisync monitors detect different screen resolutions
- How to get power from PC to your circuits
- How to read audio CDs using CD-ROM
- Joystick port information and circuits - almost all you wanted to know about computer joystics
- PC mouse protocols
- PC power supply connectors
- Publishing circuit diagrams on web
- Soundcard performance test results
- Soundcard tips
- Use disk drive motors in our projects
- VGA card information
- VGA timing information
- Ground loop resources page - lost of information about ground loops problems in audio, video and computer system, includes information how to troubleshoot and solve the problem
- PAL and NTSC timing information
- SPDIF Digital Audion Interface
- How to record telephone conversations
- Telephone line audio interfacing circuits
- Telephone line surge protection
- Telephone ringing circuits
- 0 to 10V Analog Control Protocol - information on standard analogue dimmer control protocol
- How light dimmers work with example circuits
- Cable impedance - what it is and how does it effect transmission line operation
- European semiconductor marking codes
- Plasmaball effect experiment
- RC servo motor controlling
- Resistor color codes
- Safety guidelines for building electronics equipments
Computers
Audio and video systems
Telecommunications
Power electronics
Light controlling
Other documents
FAQs I have written
Tomi Engdahl <[email protected]>