Found in 1969 Ferranti documentation, this small font is characterized by its low ripple. Transistors can be common for general use, due to the low operating current.
This circuit was found in a 1987 magazine. It measures monitors the heartbeat through a...
This crystal-controlled circuit was obtained from a 1980s documentation. The power supply should be 5...
This circuit is from 1957 Raytheon documentation. The phone must be high impedance with 600 ohms...