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Posts posted by BOHDA

  1. I try to download Rectifier Book from this page,but nothing comes!So I look for it with Google-here is the result  www.ieeta.pt/~alex/docs/ApplicationNotes/ Rectifier%20Applications%20Handbook.pdf .By same ONSEMI you can get SWITCHMODE Power Supply Reference Manual at www.onsemi.com/pub/Collateral/SMPSRM-D.PDF

  2. Hello

    I read all the question about PS.
    I have to point some things about this,as follows.
    To obtain more DC current you must use an power trafo,that means more than 150 w[better 200 or 250w].
    The best way to reduce waste power at low voltage and great currents is to split the secondary on two,that means 12V and 24V in AC.In this case you must use a switch.
    Instead of a single 2N3055 it is possible to use 2-4 pieces mounted in parallel.Each 2N3055 must have an resistor 0.1 to 0.22 ohm at 5 to 10 watt.
    For driving more transistor in the case above I think is better to test a BD139 instead of 2N2219[Whis an beta greater than 100].
    I have attached schematic of a very good PS which was very well tested,as a suggestion to try modifications.


  3. Sorry about my previous reply.I make an txt,instead of simple message.So I rewrite the previous with some adnotations.
    I have buid the LC Meter.It works fine.I use the same hex that Kiriakos has mentioned.Also I use an 2x16 display because I did not have an 1x16[is HD44780 type].
    All characters are displayed,even they are now separated on two lines.
    The PCB is good,only in schematics are some minor mistakes.
    I think the problem is,if the MCU was right written,in some bad conection between MCU and LCD display.You have to respect the PCB
    Also you can contact Fenard,is open to consulting.
    The values for oscillator are 400 pF and 49 uH.
    I also do not use RS485 on PCB[ no conection between MCU and RS485].Fenard wrote to me and advise for this.
    The working of LM311 oscillator is ease to detect by an oscilloscope,or an rf voltmeter[even on DC scale of DVM you can see at the output of LM the variyng voltage]

  4. Anyone tried to build the "LC Metre" from site's New Links?


    I breadboarded the logic circuit and tried with LCV100803.HEX(flash), LCEEV100803.HEX(EEPROM) files for the AT90S2313 u-C but the LCD works funny. It displays only the first 8 characters from the messages while they had up to 16 characters. :(
    I know it should be an one line LCD and mine was 2x16 but this should not cause any problem. LCD internal character addressing is the same for the first line, nomatter how many more lines the LCD has. I tried 4 different LCDs, 2x16 and 2x20 but all displayed the same.
    I'm pretty sure that my connections are ok(the schematic has a few errors but I corrected them). The problem must be on the firmware.

    Anyway, I just want to check if it really works as an LC meter and its accuracy is ok. If yes I could spend some time to hack a bit the code and build a PCB for it.
    The results so far have dissapointed me. :-\



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