Found in a 1967 Electronics World, this preamplifier uses an integrated circuit from that time, difficult to obtain today. The maximum frequency is 15 kHz.
This is a circuit that appears several times in this section and in articles. It is a preamplifier for...
This circuit, found in a 1992 documentation, uses an uncommon integrated circuit today. With few...
This circuit was found in Philips documentation from 1967. The phototransistor is from that time,...