50 kHz optical receiver (CB20690E)

This circuit for light modulated in frequency (FM) was found in documentation of the 90s. SUS is uncommon today, but transistors admit equivalents.

| Clique na imagem para ampliar |

Non-Inverter Amplifier LM139 (CB14242E)
The circuit below shows how to use an LM139 comparator or series equivalent as an amplifier. The...
Visible light receiver (CB7851E)
We found this receiver circuit for modulated light in a 90s Popular Electronics. Equivalent audio...
5 LED Log Scale with U257B (CB25442E)
The circuit was found in the February 1992 Radio Electronics magazine. The scale can be changed by...