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Newbie here need help

Discussion in 'General Electronics Discussion' started by Sum ting Wong, Mar 5, 2018.

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  1. Sum ting Wong

    Sum ting Wong

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    Mar 5, 2018
    Can I replace the um66/U2 in this circuit with a buzzer? And if yes what are the components in this circuit that will be removed? Screenshot_20180223_192726.png
     
  2. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

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    Jan 21, 2010
    Sure. Connect the buzzer between where pins 2 and 3 are and remove all the stuff from between pin 1 and ground.

    The buzzer will get about 4.5 volts. If you want to increase that to closer to whatever the supply voltage is, remove D10 (you'll get the supply voltage less a few volts).

    There may be more you can do, but I can't see the whole circuit.
     
    Cannonball and Sum ting Wong like this.
  3. 73's de Edd

    73's de Edd

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    Aug 21, 2015
    Sir Sum ting Wong . . . .

    Amazed to see that you are still around . . . . . totally thought that we had lost you !
    http://i1.ytimg.com/vi/4V8zkhfDGMw/maxresdefault.jpg

    Looks like that specified acoustical alarm circuit is additionally using an extra transistor to be able to adjust the volume.
    What I really like to use, is the almost free piezo transducers that are used in smoke alarms.
    Usually the cast off alarms are found for a buck at garage sales or thrift stores.
    There is a possibility that you possibly might be needing to acoustically muffle its output .
    If you were thinking of a mechanical buzzer, that would be my absolute last choice, due to high power pull and arcing contacts.

    CIRCUIT REDEDICATED TO DRIVING A PIEZO . . . . .

    upload_2018-3-5_4-40-23.png


    73's de Edd
    .....
     
  4. Sum ting Wong

    Sum ting Wong

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    Mar 5, 2018

    Thank you so much for the info sir
     
    Last edited by a moderator: Mar 6, 2018
  5. Sum ting Wong

    Sum ting Wong

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    Mar 5, 2018
    Here is the full diagram 73's de Edd already posted
     

    Attached Files:

  6. Sum ting Wong

    Sum ting Wong

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    0
    Mar 5, 2018

    Sir another question, What can be an alternative for sl100 transistors?
     
    Last edited by a moderator: Mar 6, 2018
  7. 73's de Edd

    73's de Edd

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    Aug 21, 2015
    Just about any small signal NPN, if driving the meager power needs of piezo driver unit.
     
    Sum ting Wong likes this.
  8. Sum ting Wong

    Sum ting Wong

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    Mar 5, 2018
    Ok thanks a lot sir
     
  9. Sum ting Wong

    Sum ting Wong

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    Mar 5, 2018
    Sir I've already done building that circuit but I don't know what's the use of potentiometer?
     
  10. 73's de Edd

    73's de Edd

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    Aug 21, 2015
    Sir Sum ting Wong . . . . .

    This whole circuitry functions as a detector circuit for protecting a plugged in A.C. powered device from being damaged by a high line voltage situation, or a low line voltage situation.
    High voltage being mainly detrimental to some electronics and lighting lamps , while low voltage would relate to A C motors.
    In normal voltage situations the RL1 power relay provides power to your unit plugged in, then in the case of hi or low voltage limits being met /or/ exceeded, the relay drops power to the device.
    On return to normal line power, the alert notifies of normal conditions returning and the RL1 relay reinstates AC power.

    There were 3 potentiometers, of which you eliminated 1 of them . . .RV3 . . . when you simplified the piezo driver circuitry.
    Now there are the RV1 and RV2 pots that each of them have to be adjusted to . . . .say . . . . a + 10% high voltage and a -10% low voltage threshold.
    Certainly you won't have a VARIAC . . .variable voltage transformer . . . to swing the AC power up and down, but might you have access to using one from someone else / a business / a college ?
    If not, I will fill you in on two other work around procedures . The next of which, involves a small 230VAC to 24VAC control transformer . . .which you might have the same situation of having no known borrowing source .

    Waiting for your info . . . . .

    73's de Edd
    .....
     
  11. Sum ting Wong

    Sum ting Wong

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    Mar 5, 2018
    As I browsed through the internet I see this one, what I want to know if there is a way to put a exact limit for the high and low voltage supply, for example I want the limit for high voltage supply is 230v if the supply gets higher than that the load will turn off, and the same with low voltage supply if I limit it by 180v and if the supply voltage get less than the limit value then the load will turn off.

    I already tested the circuit I run it with a 200v supply and the there's no supply to the load and I put it with a 230v supply no supply to the load either. I was wondering if it is really working because I can't find a stable 220v supply even using AVR and UPS still no 220v to test it. I want to see of it will really work in 220v supply.
    Screenshot_20180308_075000.png
     
  12. 73's de Edd

    73's de Edd

    2,770
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    Aug 21, 2015
    Sir Sum ting Wong . . . . .

    You say . . .

    I already tested the circuit I run it with a 200v supply and the there's no supply to the load and I put it with a 230v supply no supply to the load either. I was wondering if it is really working because I can't find a stable 220v supply even using AVR and UPS still no 220v to test it. I want to see of it will really work in 220v supply.



    If you measure the line voltage at your house electrical socket don't you then read 220VAC as being the normal house supply voltage ?

    What equipment were you using to be able to get what you say was :
    I run it with a 200v supply and the there's no supply to the load and I put it with a 230v supply no supply to the load either.

    And that supply should be a 200VAC and 230VAC . . .not 220 nor 230 VDC voltage.

    Since I now know what upper and lower voltage limits you want, we can accomplish two testing voltage references by using a 220VAC to 12VAC transformer and it can be of a very small wattage rating.

    73's de Edd
    .....
     
  13. Sum ting Wong

    Sum ting Wong

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    0
    Mar 5, 2018
    I'm already using 220VAC to 12VAC with a 750wattage rating
     
  14. 73's de Edd

    73's de Edd

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    Aug 21, 2015
    Explain exactly how you are presently using that 220 VAC to 12VAC transformer at that HEFTY of a current rating, unless, possibly that transformer is being related to an UPS type of application to convert 12VDC on up to 220VAC . . . . . and you THEN want to use this newly built circuit to monitor that 220AC output .

    If so, we can initially use that transformer to get and set /calibrate your circuit to a high of 132 VAC or a low of 208V AC.

    ASIDE COMMENT:
    Looks like Carbon monoxide detectors should be available in GREAT GOBBETY- GOBS's, for free, for their components and that LOUD piezo unit in the future . . . . .
    The rest of the story . . . . . . .
    Seems like my NIGHTHAWK CO detector went off over the weekend and I had 3 AA batteries at the ready, EVEN though the cells in the unit tested at --> 75%..
    Replacement left the same Err display and a big X crossing over what looks like a logo for the detector cell . . . .PLUS . . . at no extra charge . . .BEEP . . .pause . . . . BEEP . . .---> --->

    LOOKS like all manufacturers are now incorporating a countdown timer to deactivate the units to fault mode after " expected unreliable CO detector cell performance after their use of ~ 7 years".
    I tried all reset possibilities on pin 4 of the PIC16L625 series u/p, both, with and without a functioning clock. No reset possibilities resulted.
    Soooooooo I now have ONE GOOD and LOUD Piezo sounder in the Junque good parts pile .
     
    Last edited: Mar 16, 2018
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