Found in the August 1993 Electronics Now magazine, this circuit employs two symmetrical source 741 op-amps. The output is fed to a true RMS measurement circuit.
Analog Devices AD7768 24-bit sigma-delta (Σ-Δ) ADCs include an Σ-Δ modulator and digital filter...
We found this circuit in 1980s documentation. It can be used independently as CW or by exciting a...
A modulated (flashing) siren using the four gates of the 4001 integrated is shown in the figure....