This tester was found in a 90’s Popular Electronics. The integrated circuit is CMOS 4011. The indication is made through LED.
This Radio Electronics circuit, in an 80's edition, decodes the 67 kHz signal used at the time to...
This circuit was found in a 1966 General Electric documentation. The circuit makes use of PUTs...
This circuit was found in an old Electronic Design. It makes use of sidacs and operational not very...