This circuit provides a high intensity pulsating signal to a speaker. The circuit is from an American 90's documentation. The power supply is 12 V.
This circuit was obtained from an old American documentation, and practically any general-purpose transistor...
This circuit is intended for monitoring an environment. It fires a relay with a sound, but only if...
This circuit is from an old documentation, but perfectly current. In place of the battery, 2 or 4...