This simple tester was found in a Popular Electronics from the 90s. The circuit is powered by two 9 V batteries since it requires a symmetrical source.
This circuit is from the Philips manual of 1990. The integrated circuit is not very common. The...
We found this configuration in a 1974 technical documentation. The circuit consists of a filter to...
Other operational amplifiers in the series, such as the MC34072, MC34074, MC35071, MC35072,...