This circuit with the 555, was obtained in a 90s American documentation. The signal must be applied to a good amplifier. The sound is similar to that of a police siren.
With a light pulse on the Q1 sensor the circuit turns on and locks. To switch off, a light pulse...
March 2017 - STMicrocoelectronics' new LoRaWan B-L072Z-LRWAN1 STM32 development board can now be...
This circuit is from the manual of the components used, from the 80s. The circuit is valid for...