Currently on the market selling a variety of Electromechanical hours in a variety of houses and parrots. As a rule, the manufacturer of these devices is not specified. Take the liberty to say that in a very short time after purchase by the owner, in the best case, give "the house" for the game to children, as did my friends.
I watch caught my eye when I thought about what kind of alarm clock to put in next watch an ENCORE CRIC. The aforementioned "house" alarm emits nice tone and is mounted on the circuit Board size 32x16 mm overall, dismantling cost and neatly sawed off the battery compartment from the exterior, after a little work got a good warning device.
The principle of refinement is clear from the figure.
In my case was observed periodic pozvanka which elimination is sufficient to establish the types of capacitor C1 KLS, Km, KD, or any small-sized. Structurally, the transistor T1 is installed on the Board hours into the pre-drilled holes, the withdrawal of the base folded up. Resistor R2 and capacitor C1) with one end soldered to the base of VT1, and the other to "minus" the conclusion of the Board. The findings of the electromagnet should unsolder from the Board. Radiator for convenience, I resolder on the opposite side of the Board. The Resistor R1 in my case was installed on the motherboard of the electronic clock.
In standby mode, the call consumes little current (less than 0.5 μa), TT - not more than 3 mA from a 1.5 V battery). Alarm satisfactorily audible by reducing the supply of 1 V.
Author: S. Polyakov, G. Narimanov of Astrakhan region.