The integrated circuit used in this amplifier is not very common today. This amplifier was found in the 1977 National Semiconductor Audio Handbook. The power source must be at least 500 mA.
This series LED circuit was found in the February 1992 issue of Radio Electronics magazine. The...
We found this circuit in the Linear Applications Handbook by National Semiconductor. The circuit uses...
The noise comes from the PN junction of a common silicon diode. Since no gain is given by the...