We found this circuit in a 70s RCA manual. The circuit uses an LDR by directly driving a sensitive relay. Resistor R1 is 5.6 ohms and R2 is 25k. The pot is 10k of wire.
This circuit converts square (rectangular) signals into triangular signals with typical 16 V...
The transistors of this circuit found in an English 1980s documentation may be the modern BC548...
In the figure we have an AND gate with the LM3900 operational transconductance amplifier. The...