This high impedance headphone amplifier was found in American documentation from the 1990s. Any general-purpose FET can be used.
This circuit is based on a Texas Instruments LinMOS integrated circuit consisting of an...
This sophisticated logic probe for 5 to 12 V circuits (CMOS and TTL) was found in a 1980s...
This 2005 Linear Technology circuit has separate outputs for monitoring the charge and discharge...