This circuit was found in an Elektor from the 90s. It makes use of digital CMOS integrated devices common today. The signal is controlled automatically sequentially.
This very low frequency amplifier has a gain of 1,000 and was found in a 1967 documentation. The circuit is...
Many oscilloscopes have high impedance inputs that make it difficult to observe high frequency signals...
This experimental amplifier was found in the 1960 Mullard transistor reference manual. The...