We found this circuit in a Poptronics from 1998. The circuit can be extended to more competitors with another 4011. The power can be made with voltages from 6 to 12 V.
This low-pass circuit was found in the December 1990 issue of Radio Electronics magazine. The...
Found elsewhere in this section, but from other sources, this circuit is from a 1964 Electronic...
This circuit came out from the Linear Circuits Applications of Texas Instruments, based on the...