This circuit was found in a 1968 General Electric manual. The circuit is for 3 A motors but can be changed according to the SCR used. The SCR is type 106 and R1 is 10k.
The circuit shown in figure 5 generates square signals based on a transconductance operational amplifier...
By adding a transistor to the output and some polarization features we can obtain a higher output...
Found in the 1990 special issue of Radio Electronics Experimenter magazine, this circuit uses an...