This interesting circuit uses a sodion valve that we have already described in an article on the website. The circuit uses several batteries for power. The phone is of high impedance.
120 degree lagged signals can be obtained with the simple configuration shown in the figure....
This circuit was obtained from a Popular Electronics of the 80's. It is set to a certain pulse...
In the figure we have an application of ON Semiconductor's own semiconductor manual from the 80's....