User:Mahjongg/sandbox

Specifications
http://www.next.gr/power-supplies/high-voltage/

Resonant inductive coupling

SAP-1 computer (Simple As Possible) 8-bit homebrew CPU

HDMI to VGA cables do not work! They rely on logic incorporated in a videocard that isn't available in a PI. Somehow such a videocard outputs analog signal on the otherwise purely digital HDMI connector, that seems to be the only way for it to work. But normally HDMI cables never carry analog signals and the PI surely doesn't output analog signals either, almost no HDMI output device does, as its completely against HDMI specifications.

What does work is a HDMI to DVI-D cable, connected to a DVI-D monitor, that is because both HDMI and DVI use the same kind of digital signaling (LVDS). Only DVI-D misses the signal channel for audio.

HDMI to VGA adapters do work, they convert the digital serial data streams from HDMI and using complex logic, and digital to analog converters they convert the HDMI signal to the analog signals needed for VGA, and sometimes also convert HDMI audio to an analog stereo signal. But note that if they feed off the PI it can cause a problem, as the PI only is designed to provide about 50mA to the HDMI/DVI-D monitor, and these adapters use >200mA, while the absolute maximum the PI can let through is 200mA. These adapters also thus use about half the energy that the PI (without USB devices) uses. Therefore its much better to use an adapter that has an external power input. Alternatively there are HDMI dongles (male to female HDMI adapters) that have a barrel input connector to feed the adapter with.

Townsend discharge Paschen's law

http://www.retrogamer.net/forum/viewtopic.php?f=1&t=35230 http://www.icongames.com.br/msxfiles/blog-en/laser-squad-msx/ http://retroasylum.com/phpbb/viewtopic.php?f=21&t=1317 http://tvtropes.org/pmwiki/pmwiki.php/Main/ZXSpectrum

The GEM 1000 Junior Computer, also known as the French Charlemagne 999 was an obscure low cost toy Home computer for children from 5 years upwards, produced in Taiwan by Rabbit Computers of Hong Kong, Little more is known about the machine which was also sold as the even more obscure Rabbit RX83, (which was a downsized version with even less RAM, just 2K) and which design may also have led to the Brazilian MC-1000 from Comércio de Componentes Eletrônicos. It was part of a family consisting of GEM 1000, GEM 2000, GEM 3000 and GEM 4000 systems.

History
The GEM 1000 was released In a market already saturated with cheap machines with very similar features. It did not arouse much attention. The fact that it wasn't a "clone" of similar 8-bit systems (like the Apple, the TRS-80 or even the Sinclair Spectrum) certainly did not contributed to its popularity.

In addition to the poor design and "Chiclet keyboard", the GEM 1000 had only 16 KB of RAM (small, even by the standards of 1983). Like the Sinclair Spectrum the commands of the BASIC, (which was similar to the Apple 2's Applesoft BASIC) were typed by pressing a single key. The French Charlemagne 999 system used a version of this BASIC that used French instead of English keywords.

Technical specifications

 * CPU: Zilog Z-80, 3.57 MHz
 * Memory: 16K RAM, expandable to 64K RAM; 8K ROM
 * Keyboard: 50-key rubber Chiclet keyboard QWERTY based, even for the French system
 * Display: Based on Motorola MC6847 32×16 text (8 colors), 128×64, 128x96, 128x96, 128x192, 128x192, 256x192 graphics (2 background, 3 foreground colors)
 * Sound: General Instruments PSG AY-3-8910, 3 voices, + White noise
 * Ports: interface cassette recorder 1200BPS, TV output Connector joystick
 * Hardware Sprites: None

History
The RX83 was released In a market already saturated with cheap machines with very similar features. Even with the attractive price of U.S. $ 99, it did not arouse much attention. The fact that it wasn't a "clone" of similar 8-bit systems (like the Apple, the TRS-80 or even the Sinclair Spectrum) certainly did not contributed to its popularity.

In addition to the poor design and "Chiclet keyboard", the RX83 had a 2 only KB of RAM (very small, even by the standards of 1983). Like the Sinclair Spectrum the commands of the BASIC, (which was similar to the Apple 2's Applesoft BASIC) were typed by pressing a single key.

Technical specifications

 * CPU: Zilog Z-80, 3.57 MHz
 * Memory: 2K RAM, expandable to 64K RAM; 8K ROM
 * Keyboard: 50-key rubber Chiclet keyboard
 * Display: Based on Motorola MC6847 32×16 (8 colors), 128×64 graphics (2 background, 3 foreground colors)
 * Sound: General Instruments PSG AY-3-8910, 3 voices, + White noise
 * Ports: interface cassette recorder 1200BPS, TV output Connector joystick
 * Hardware Sprites: None