This is a typical 3 ½ digit TTL counter. We found it in the September 1973 issue of Radio Electronics magazine. The circuit is to be powered by 5 V. It can be expanded to more digits.
This analog thermometer was obtained from an English documentation. The sensor is a common diode...
Found in a RE Experimenter Handbook from the 90s, this circuit is intended for the use of LEDs in...
This noise limiter for low intensity signals was found in a 73 magazine for radio amateurs from the...