Jump to content
Electronics-Lab.com Community


  • Posts

  • Joined

  • Last visited


Posts posted by SatthisCy

  1. Stath,
    I am not clear why you are using an adjustable regulator, then you have an additional adjustment pot after the regulator.

    The second pot (POT2) is not part of the supply cct; it is part of the measuring cct.
    The resistence of the voltage divider (680kohms +the POT2) is very high so i think that its load is negligible .

    If you must have an isolated ground, you can use a higher voltage regulator and lift the ground up from common with a resistor.

    I've tried this with a simpler way ; i lifted the measuring ground from common by using a resistor. Same, bad resutls!

    I have also seen a post from ante where he coils a piece of wire and puts it on the transformer to make an isolated tap. Then rectifies it as an isolted small voltage supply.

    This is interesting!

    A Question...
    ?? Do transformers can use for step-down in DC source as their are used in AC sources?

    Thanks MP


    I cant get the idea of using an inverter. what i can acheive with this?

  2. Hi,

    i have to say that i had the same idea few months ago.

    A device that counts how many people enters a single door; e.g. a restaurant.

    I was thinking of using an optocouple or ir emmiter and transmiter. when the ir light that the emmiter receives is interrupted by a human body, it produce a reset of a flip-flop or a clock and produce an increment on a counter.

    counter`s outputs update a BCD decoder state .

    This is an overview of my idea...

    i dont know ecxactly what IC`s are suitable for this but you have to make a little search on logics gates - counters, encoders- decoders, 7-segment display.

    if you have Multisim 7 software may be very useful

  3. HI.....
    MP, plase take a good look , the sample for the measuring point is taken on the middle point of a voltage divider of >680kohms

    And i remind you that this proplem is solved then i supply the voltmeter circuit from a 9volts battery... This is the mystirious fact for me.

    ??> The datasheet of the LCD panel says:

    That's why there is no problem when i supply the cct from a battery; battery is a separate source from my cct!!!

    Thanks to MP, and audioguru.

  4. Hello to every one!! this is the first time firsttime im writting to forum.

    i found this website the most usefull for me since im a student in elect. eng.

    i hope that someone will help me with a problem i had building a LAB P.S.E

    I used a power supply from an old destroyed printer. I did some measurements and it was working JUST FINE!

    OUTPUT 1: 24v @ 2.5A
    OUTPUT 2: 5v

    So, i decided to build a subcircuit using an LM317 regulator to adjust the 24v output, and a volt meter using an LCD. I was 100% sure that it will work!

    I built it, power it up, and .......... The voltmeter was indicating INFINITE VOLTS!
    I found out

  • Create New...