This powerful sound emitter used in defense to intimidate people was found in a 90s Popular Electronics. The circuit produces a strong modulated tone of 3 kHz. The modulation is 10 Hz.
The integrated circuits used in this 1999 project are not very common today. However, they can be...
This 3-digit thermometer, suggested by Texas Instruments, uses 3 integrated plus the display, with...
This circuit is from the National Semiconductor FET Databook. The coil data is provided with the...