Share a crying alarm circuit diagram

Here is the weeping alarm circuit diagram:

Components List:

R1, R5 4.7K

R2______ 47K

R3______________ 10K

R4______________ 100K

Rx______________ *See text

C1, C4__________ 100uF/25V, electrolytic

C2, C3__________ 0.01uF (10nF), ceramic

T1_____________ 2N3702 (NTE159, TUP, etc.)

IC1, IC2________ LM/NE555, MC1455P, etc.

LS_____________ Speakers

This alarm circuit uses a timer IC to generate the frequency. This circuit has a wide range of supply voltage from 5V to 15V DC.

*The speaker LS and the resistor marked "Rx" should be 75 ohms. If you have a standard 8 ohm speaker, Rx is 67 ohms. The closest value is 68 ohms. So for an 8 ohm speaker, Rx is 68 ohms. For a 4 ohm speaker, Rx is 71 ohms, for a 25 ohm speaker, Rx is 50 ohms, and so on.