Found in National Semiconductor publication from the 1980s. This gain-100 circuit can be implemented with equivalent modern components, including lower voltage supply.
Using the LM3909 this circuit was found in the January 1992 issue of Radio Electronics magazine....
This circuit allows the coding of several relays from coded keys that must be activated, according to...
To power small projects, we found this circuit in the Radio Electronics magazine of May 1977. The...