The circuit below is suggested by National Semiconductor in technical documentation on the LM3909. The circuit is powered by a single battery and has a very low consumption.
This analog volt-ammeter was found in an Electronics World of 1968. It makes use of a 0-1 mA...
This is one of the many possible siren configurations for the 555 integrated circuit. We found it in...
This circuit was found in an Electronics World magazine from 1990. The circuit can be mounted...