The device is useful for a model fire truck and a guard system. The intervals between the signals and their duration is controlled by changing values of electrolytic capacitors C1, C3, fixed resistors R2, R4 (see diagram). Sound effects you can Supplement the indicator light, replacing the resistor R3 with a bulb from a pocket lantern 2,5ВХ0,1A. Output transformer and speaker from any small-sized transistor radio.
Recommend to read
Ultrasound against rodents
Among elastic oscillations of air, ultrasound (from Latin ultra — beyond, more, above), inaudible to the human ear and with a lower frequency limit conventionally taken as 20 kHz, has long...
ASSISTANT DEVELOPER
We lived first in an apartment in a three-story house, and then decided to move in the house mansion. But it would require a serious overhaul, and outbuildings and is subject to complete...
