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  1. BobK

    Need help using a HI-8010P-03 chip

    It's all right there in the datasheet, but it does take some experience to read them. Bob
  2. BobK

    LED Flasher Relay Flash Rate

    I actually got 4 boards by mistake. I had offered these, plus a complete kit of parts to anyone in the U.S. for free, but got no takers :(. PM me your address and you will get a nifty LED flasher kit free of charge. Bob
  3. BobK

    about diodes

    A 1N4148 actaully has a recovery time of 4ns. Bob
  4. BobK

    LED Flasher Relay Flash Rate

    One advantage of Eagle is that it is the software of choice for BatchPCB, which is great resource for hobbyist 1-off PCB manufacturing. But I find Eagle very difficult to use. I spent all weekend trying to incorporate the parts I actually use into 1 library so I don't have to go through...
  5. BobK

    need help to display on LCD

    Your C compiler library probably has code to drive LCD displays. If not, Google will find many variants of it. Bob
  6. BobK

    Need help using a HI-8010P-03 chip

    Ah, okay. You shift in 38 bits of segment data by putting the data on the DIN and then pulsing ~CL low then back to high for each bit. After the 38 bits have been sent, you pulse LD high then low to transfer the shifted data to the output latches. Quite simple, really. Bob
  7. BobK

    Mosfet cir.

    You could use the 12V without regulating it down. The trick is to switch the 12V circuit with the 3.3V signal. An LM317 does not help with that. This is simply done with an NPN transistor and 2 resistors, but then the signal is inverted, so you would need two of these stages. A better idea...
  8. BobK

    Mosfet cir.

    The gate of the MOSFET requires as much as 4V to turn on even a little bit (200uA) and 10V to fully turn on. Look for a logic-level MOSFET if you want to turn it on from 3.3V or use a level translator to switch 12V to the gate. Bob
  9. BobK

    Need help using a HI-8010P-03 chip

    As an option, there are PICs that have built in LCD segment drivers. Bob
  10. BobK

    am I in the right place?

    Ah, you might be right. It was not clear in the OP. Bob
  11. BobK

    Help using TIP42c

    The minimum gain of the TIP42C is 15, so to get 6A, you will need 400ma of base current. That would require about a 27R base resistor. But that current is too much for a 2N3904. A 2N2222 would work, and you would have to reduce it's base resistor to abo 680R. And both transistors are...
  12. BobK

    3.3v psu

    There are plenty of fixed 3.3V regulators that will do the same job with only 3 parts (regulator + 2 caps.) Bob
  13. BobK

    Tinning Explained

    For SMD work I use the same rosin core solder, but I flux the pads and pins before soldering. This just makes the solder flow better. They may have been refererring to the diameter when they said it was not suitable for SMD work. Bob
  14. BobK

    Is this true or false

    Yep: Solar Panel (Wikipedia) bolding mine. Bob
  15. BobK

    Simple way to salvage a car charger?

    Charging at 12V will get your battery to about 10% of capacity, so this will not work. A lead acid battery charger should provide a constant current with the voltage limited to 14.4V max. http://batteryuniversity.com/learn/article/charging_the_lead_acid_battery Bob
  16. BobK

    Is this true or false

    It does not, unless you have some very fast rectifiers! On the other hand, solar panels work nicely. Bob
  17. BobK

    Stepping down 12vdc to 6vdc, max 1amp

    The current on this is likely so low that a 6V zener diode in series with the power lead would probably do the trick. Edit: I now see in the title you mention 1A. Does the digital thermometer really take that? I would expect it to take a few milliamps at most. What kind of a battery is it...
  18. BobK

    am I in the right place?

    This project is fairly simple for someone well versed in microcontroller programming. Without a microcontroller it would be a quite advanced project, needing on the order of 10 or more logic chips. In fact, I am not even sure how one would go about it without a microcontroller. Basically...
  19. BobK

    Help using TIP42c

    Great! Glad to be of help. If you need much more than 1 amp you will have to lower the 470 Ohm resistor. Bob
  20. BobK

    Tinning Explained

    I think 1.2mm is too big. I use 0.022 in or 0.5mm solder. Also agree with Dave, I only use flux when doing surface mount, rosin core works without flux for all through hole work. Edit: if the solder is just beading up and dropping off, your iron is too hot. Bob
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