This circuit for RF measurements at 200 MHz was found in no documentation two years 80. At a sensitivity of 1V peak and the components used are still common in these days.
This circuit is from National Semiconductor documentation. The operational amplifier is of the...
In the figure we have the way to add hysteresis to an operational amplifier. The relationship...
This circuit, from an American publication of 1974, provides a 0.005% regulation with a variation of...