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.
This circuit can be applied to several logics. The circuit is from an Electronics Now from the...
This simple circuit with SCR and unijunction transistor appeared in Radio Electronics magazine in July...
This timer was found in a 1980 publication. With the BC548 for Q1, an 8-ohm speaker with 6 V power...