Advertisement
TESTING THE SM3
For testing your SM3 you'll need:
• A speaker with an impedance from 3 to 45 ohms. Any style will do, but a horn type will give the
volume.
• Power source from 9 to 12 volts DC. A 9 volt battery will suffice for now.
• Pushbutton switch. A doorbell button works well, but simply touching two wires together will do.
1. Connect up the speaker to points 1 and 2.
2. Connect your pushbutton (or wires to touch) between point 4 and point 3 (the + power connection).
3. Connect ( + ) power to point 3 and ( - ) ground to point 5.
4. Depress the button and you'll hear the characteristic upward wail of the police siren.
SM3—5
most
Advertisement
