Inside a 9-Volt Battery - RF Cafe

Simple Solid-State Circuits for the Experimenter, September 1972 Popular Electronics - RF Cafe

Philco Models 39 and 39A, 6-Tube Dual-Range Battery Superhet, May 1936 Radio-Craft - RF

Belmont Model 5P19 Radio Schematic and Parts List, September 1947 Radio News - RF Cafe

The Renode - A New Gridless Tube, February 1936 Radio-Craft - RF Cafe

Build a Mini-Tenna for FM Radio, February 1968 Radio-Electronics - RF Cafe

Inside a 9-Volt Battery - RF Cafe

The Electric Motor, December 27, 1943 Life - RF Cafe

JFET's - Put Last Month's Theory to Work, June 1969 Radio-Electronics - RF Cafe

Lithium-Polymer (Li-Po or Li-Poly) Battery Characteristics - RF Cafe

Majestic Model 25, 9-Tube Twin-Detector Radio Service Data Sheet, February 1932 Radio-Craft - RF Cafe

Interference - Causes, Remedies and Location, July 1960 Radio-Electronics - RF Cafe

GE Model 250 Radio Service Data Sheet, August 1946 Radio-Craft - RF Cafe