Prolink nVidia GeForce4 MX440 64MB AGP 8X VGA Card

  Hardware Specification Graphics Engine NVIDIA GeForce4 MX440-8X GPU Model Number MVGA-NVG18AM (w/64M,TV) MVGA-NVG18A (w/64M,TV, DVI)MVGANVG18A (w/64M,VIO,DVI) MVGA-NVG18A (w/128M,TV,DVI)MVGA-NVG18A (w/128M,VIO,DVI) Video Memory 64MB DDR Memory 128MB DDR Memory Effective Core Clock 250MHz 280MHz 280MHz Memory Clock 420MHz 520MHz 520MHz RAMDAC 350 MHz TV-Out Resolution 1024 x 768 Bus standard AGP 8X Refresh Rate 60-240 Hz TV-Out support DVI Support (only for w/DVI model) Video-In Support (only for w/VIO model)  

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3dfx Voodoo3 2000 AGP (`99)

3dfx Voodoo3 1999   From 3dfx Interactive, the architect of the 3D revolution, comes a new dimension of high-resolution gaming. A snap to install, the Voodoo3 2000 AGP replaces tired, old 2D cards in just a matter of minutes. Fusing the world's fastest 2D with a dual 32-bit pipeline, the Voodoo3 2000 AGP pumps out over 100 billion operations per second to bring you resolutions as high as 2046x1536 and speeds of up to 60 frames per second. Generating 6 million triangles per second to bring to life 500 of the hottest titles, the Voodoo3 2000 AGP's Patented Single pass, Single Cycle, Multi-Texturing delivers the brilliant color and amazing clarity that has made it the standard in PC entertainment.    Product Features 128-bit 2D, 3D and video accelerator Voodoo3 graphics processor 16MB high-speed SDRAM memory AGP 2x MPEG-1, 2 playback 300MHz RAMDAC 143 Megapixels/second 286 Megatexels per second peak fill rate 6 Million polygons per second peak processing 2.29 GB per second peak bandwidth Patented Single-pass multi-texturing  Other Features Supports resolutions up to 2048x1536 DVD Hardware Assist Supports DirectX, Glide and OpenGL Alpha-Blending Single Pass, Single Cycle Bump Mapping Single Pass, Single Cycle Trilinear MIP-Mapping Programable Fog Tables Sub-Pixel and Sub-Texel Correction Gouraud…

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LCR-T4 transistor tester original firmware

Bought cheap transistor tester from eBay and currently experimenting with firmware updates. I was able to program it with this version of Markus transistor tester firmware: https://github.com/svn2github/transistortester/tree/master/Software/trunk/mega328_T4_v2_st7565 To build, use a WinAVR programmers notepad, open Makefile and select Tools->Make all. At first, was getting weir errors, but after adding msys-1.0.dll to \WinAVR-20100110\utils\bin everything built ok. Before doing firmware experiments, I have made backup of original firmware, if somebody needs it, you can download it here: Code Data Config I tried to reflash original firmware and it worked fine. For programming I use my MiniPro programmer.

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Modify Arduino 5v relay module to work from 3.3v

I am implementing a power-off function for my Ender 3 using OctoPi. For that, I need a relay and I happened to have one. Unfortunately, after connection relay to Raspberry Pi GPIO pin, the relay was always on and not listening to any commands from OctoPi. It appears this module was designed for 5v logic levels and Raspberry Pi works with 3.3v logic levels. After investigating relay one can see that its circuit is: For JC817C forward voltage Vf=1.2V and forward current If=20mA For Raspberry Pi output high (when VDD is 3.3V) is VO=2.3V 17mA So, it seems that the output of Raspberry Pi is not enough to drive JC817C. To solve this I decided to remove optocoupler from the module and connect the input pin directly to Q1 transistors base. To connect the output pin to a transistor you should limit output to appropriate current. You can do that by choosing the appropriate resistor value. I calculated it like that. From S8050 (J3Y) transistors datasheet:  DC current gain hfe ~ 120 From relay datasheet: Rrelay=70Ohm Vrelay=5V so calculated Irelay=Vrelay/Rrelay=5/70=71mA Let's choose Ic=100mA To turn it on, we must have ~ Ib=Ic/120=100mA/120=833uA ~800uA Vbe usually is ~0.7V R9 voltage…

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Learning the Art of Electronics, Week 2

[latexpage]  2L1.1 Ok, I  form a simple low pass filter using unknown RC values. Then I measure time constant using scope and 500Hz square wave. Time constant is a time it takes for a voltage to reach ~63% of its total value. Measured time constant using RIGOL DS1054z is 0.268ms ( measured using manual cursors: I set Percent for Vert. Units, then Set range of the wave with vertical cursors and then measure time to rise to ~63% (bx-by) ) Measured time constant using Tektronix 2221A is 0.270ms ( I position the wave from 0 to 100% and then using cursors get ▲T for ▲V to reach 63.2% ) t = RC Now I need to find R. And task is to measure R without removing C. We can do that by imagining that RC is just R, but we have to eliminate XC. We can do that by increasing frequency unti we get no phase shift. The higher the frequency the less XC there is. We can see that XC is not effective anymore when we see no more phase shift. I add a known 1K resistor in front of RC filter. Apply sine wave and increase frequency…

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