With this circuit of a Popular Electronics from the 90's it is possible to test a diode with the oscilloscope visualizing its characteristic curve. The transformer can have currents starting from 100 mA.
We find this circuit in a 1978 documentation. The circuit uses two inverters of a 4049 integrated...
We found this circuit in a 1986 documentation. Its purpose is to power a set of light bulbs (or...
For reference only, this is the second IF amplifier stage of a common transistor radio from the...