This is the basic configuration of an operational amplifier sample & hold circuit. The FET and transistor are commonly used. The circuit is from an 80's documentation.
This simple circuit that senses energy cables (alternating current) through the field produced was found...
This third-order filter was found in a 1975 publication. The circuit must be powered by a...
This circuit that also has a Power On reset was obtained from a 2005 Linear Technology manual. The...