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  • Users: felixc
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  1. felixc

    Dimensioning a MIL-C-26482 pinout

    Hi, I've been asked to create a footprint to accomodate a pcb version of a MIL-C-26482 Series 2 connector. The insert arrangement is 22-41. (size 22, 41 pins) So far I have found drawings of the pin arrangement and nomenclature, but I haven't seen any dimensioning for the pin layouts. Would...
  2. felixc

    Creating a Power-on reset pulse in a CPLD

    Hi, I am required to create a power-on reset pulse to trigger external registers ASAP after power-on so that valves will not open spuriously. The system reset pulse comes after one second, too late. Of course the systems are in the field now... There are no inputs that provide a delayed...
  3. felixc

    Ir LED stops emitting IR

    I'm repairing my old TV remote. (a vintage Sony with a metal-clad top for which I have the schematics) I expected the classic broken crystal or dirty contacts. What I found is the IR LED that still behaves like a diode, but does not emit light anymore. The IR emission can be easily seen...
  4. felixc

    Driving a 12V DC motor in PWM mode

    Hi, I want to drive a DC motor with a bridge in PWM mode, a little Maxon with a coil inductance of 0.4mH. I'll use an integrated H-bridge driver like the National LMD18200. How can I calculate the ideal drive frequency for the PWM? Would I need some snubber circuitry? Felixc
  5. felixc

    OTP versus soldering process

    Hi, I have the option to use OTP microcontrollers (an old 87C42) on a surface-mounted board. I am wondering if the OTP can lose its contents when it is subected to the heat of the surface mount reflow. Or should I use sockets all the time? Did anyone go through an issue like this? Felixc
  6. felixc

    Buying a used license?

    Hi, I'm not sure if the subject has been debated, but I'd like to buy AutoCAD LT2000. Autodesk does not support it anymore. As per the license contract, is it possible for someone to resell his license to someone else? (if he hasn't purchased an upgrade, of course) I want LT2000 because I...
  7. felixc

    Alkaline AA cell at 1.65 volts?

    Hi, I saw something strange. A flashlight had a leaking battery, an Eveready AA alkaline. However the flashlight was working properly. Even under load I measured 1.65 volts at its terminals, while the other batteries in the flashlight had 1.5 volts. What's special in the chemistry of an...
  8. felixc

    Remanent magnetism in a solenoid

    Hi, a friend asked me if there can be a way to reduce remanent magnetism in a solenoid in his machine tool. The coil is driven directly by a switch. He says that the solenoid still has some magnetism left after he turns the switch off. My feeling is that a zero-crossing relay may do a better...
  9. felixc

    Aluminum parts in cars getting corroded?

    Hi, are cars with aluminum parts doomed to the scrapyard earlier than regular cars, because of galvanic corrosion? My brother is a mechanics at a Ford dealer, and he says that cars like the Lincoln LS, with aluminum parts in its suspension, is hard and costly to repair when aluminum parts are...
  10. felixc

    Ozone smell with Electronic filter

    Hi, my house has an electronic filter unit integrated to the central HVAC system. It is a Honeywell unit rebranded by Lennox. Each time, after I clean the filters and put them back, there will be ozone smells in the house for 3-4 days before it settles down. Not very good for the health...
  11. felixc

    24-volt battery vehicles?

    Hi, are there countries where the working voltage in vehicles is at 24 volts? Or are there classes of motor vehicles, trucks, or maybe agricultural vehicles, that use 24 volts? One of my customers suddenly has concerns that the systems that I am working on could be used on 24-volt vehicles...

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