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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 . . . . .
View attachment 39868
73's de Edd
.....
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.
Sir Sum ting Wong . . . .
73's de Edd
.....
Just about any small signal NPN, if driving the meager power needs of piezo driver unit.
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
.....
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
.....