This current meter with many scales was found in a 80s American documentation. The operational amplifier is from that time, uncommon nowadays.
This signal follower was obtained from a Raytheon manual from the 1960s. The transistor is made of...
This circuit was obtained from a 1978 English magazine. This circuit can be easily assembled. We...
Found in a 90s American documentation, this circuit mimics the Enterprise warning signal from the...