November 2007

• If the waveform on the scope droops then you may need to use a 10X attenuating probe or mode. this attenuator is at the tip of the probe hence better measurement possible, also very high frequency signals may be best transmitted over a 50 ohm impedance matched line to the scope.Never ‘put or remove’ ICs, cards or plug-in modules when the power to that system is on, power off system wait for some time for caps to discharge, then insert ICs or cards, applies to PCs too, USB and Firewire ports are exceptions as they are hotplug, anyway even in this, take a bit of care as some peripherals may cause some problems.
• Karl Ferdinand Braun - In 1897 he built the first cathode-ray tube…oscilloscope. CRT technology is to this day used by most television sets and computer monitors. The CRT is still called the “Braun tube” (Braunsche Röhre) in German-speaking countries (and in Japan: Buraun-kan).
• The inventor and developer of oscilloscope as a useful measuring instrument is Tektronix.
• Have a lathe lamp or table lamp with a 40W edison-filament lamp (ordinary bulb) on your workbench.
• Have an antistatic mat on the work or test table, if you cannot afford or get it then get a large aluminum sheet, laminate it with an insulating polycarbonate sheet and earth the metal plate with two 1M resistors in series.
• Use thin multi strand teflon wires for your jumpers within a PCB, these are not damaged by your iron too.
• Silicone shrink sleeves can withstand high temperature and use this in your work to make it safer and neat.
• When you make a connection with a wire you need mechanical strain relief or on use connection will open.
• Test a NPN transistor, DMM in 200K range. emmiter negative probe, collector positive probe, it should show open. while still holding that way press wet finger on base and collector, it may show some reading, then it is ok. for PNP swap probes polarity and do the same thing. the wet finger when pressed applies a base current in uA.
• Testing a Mosfet - Transistor Tester - Testing Transistors - Basic Testing of Semiconductor Devices
• Teflon tape can be used to make leak proof pneumatic or hydraulic connections if junctions are leaking.
• Gold plating is used in connectors because it has low contact resistance and does not corrode or react
• Persistence of vison around 16 frames a second (60mS) hence very fast events not seen, see in wikipedia.
• Use a 100uF and 0.1uF CD in parallel to filter because the inductance of 100uF is a lot (the electrodes are wound as in a coil) and high frequency passes over and is filtered by the 0.1uF which has negligible inductance.
• Try to use same family ICs in a circuit, like only LS or only HCT, if you mix up then you have to do a design review.

Digital Clock Web Gadget for Date and Time

This Web Gadget is for the Google Homepage, Web-page or blog. It has seven segment display, similar to traditional Digital Clocks in the dashboard. It will also indicate the date and week.

Add to Webpage

seven-segment-digital-clock The Project Page

The javascript is as close as possible to a c program that you could write for a PIC processor, So then try and make a gadget which is 3D, using PIC or 8051.

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