Door bell timer using 555 IC?

[Refugee]

I would be prepared to say that the iron losses in the transformer would consume much more power than biasing the transistor.
I am pretty sure that a large MOSFET would be able to drive a DC bell directly and they also have the back EMF diode fitted internally.
Place the MOSFET where the first transistor is and swap the timing resistor and capacitor over so that the FET switches off when the capacitor charges up.
A limiting resistor of a couple hundred K ohms in series with the gate would be needed.
FETs turn on with a simple wet finger and can stay on long enough that they read short circuit with an analogue meter if the gate is not discharged.