In this 1990s circuit, found in a National Semiconductor manual, the output voltage is the square of the input voltage. The components are from the period.
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...