This circuit uses a crystal phone and can be built with more modern transistors like the BC548. The original circuit is from a 1979 publication and is powered with only two AA or AAA batteries.
This circuit shows how to use the 4007 MOSFETs in an amplifier stage. We found it in an...
September 2017 - STMicroelectronics STBR3012-Y high voltage rectifier for automotive use is in...
This first order filter that can be implemented with any operational amplifier was found in the...