This simple logic test circuit with 3 LEDs was found in October 1985 Radio Electronics magazine. The power supply is according to the logic, and this version is indicated for TTL.
This is a combined circuit of tone generator and preamplifier. We found it in a 1975...
We found this simple alarm circuit in a 1986 documentation. The circuit uses sensors of the NA...
We found this circuit in the Linear Applications Handbook by National Semiconductor. The base is...