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sir i know these circuits are same.only one difference is present in my circuit i.e
when the water doesnot com from the well or dry.circuit will beep.and alert us.
The BC548 was an inverter and can't just be removed without other circuit changes.
The circuit you attached has a very old SL100 transistor driving a 200 ohm relay coil from a 9V supply. Then its current is only 9V/200 ohms= 45mA. Any little NPN transistor can drive the relay coil.i have circuits that use SL100, but i can't find this transistor.
so what can i do. plz help me.
try to use 2N5551 with proper pin out(you need to check). they are generally available in market as used in telephones.i have circuits that use SL100, but i can't find this transistor.
so what can i do. plz help me.
The Cmos ICs with a 12V supply will have an output current of 11mA to 22mA if it does not have a current-limiting resistor. But then the output transitor of the IC will get too hot if it directly drives the base of an NPN transistor that has its emitter grounded.
But the 10k base resistor limits the base current of the transistor to only about 1.2mA so the transaistor's load current can be only 12mA to 24mA.
The circuit appears to be designed by somebody who knows nothing about transistors.
No.Yup, i only need a small collector current for the transistor. The current will be used to trigger the gate of the SCR... (just to switch the SCR into ON state).
It might be a lot of current.