This circuit was found in a 1967 Electronics World. Transistor Q1 can be a TIP321 and Q2 can be a BC558. The indicator lamp is optional.
This circuit, found in a 1994 publication, allows the use of two common analog telephone sets on a...
This 1967 General Electric circuit makes use of an array of 3 (integrated) transistors for an...
This modulator circuit for low intensity signals is from old documentation. The integrated circuit...