This circuit accurately monitors a 5 V TTL source. The circuit is from National Semiconductor's Linear Applications Handbook.
This circuit was published in an English magazine from 1977, but it can be easily assembled since...
The maximum current of this circuit is 1 A. The circuit is from Motorola Linear Interface ICs from...
This circuit is a handset receiver that picks up the signal emitted by a coil under the rug or...