This circuit was found in a documentation of the 80s, having didactic purpose. For R1 values between 10k to 1M can be used. Transistors are general purpose types.
In this circuit, which uses only diodes, we have both simultaneous functions. The diodes are...
This logic tester circuit was published in the November 1980 issue of Radio Electronics magazine. The...
This circuit was found in a 90s Popular Electronics. The circuit uses 4 bicolor LEDs to indicate...