Applause Meter Tube Powered 1953 How-To Build PLANS

LIE DETECTOR / POLYGRAPH Vintage 1953 How-To build PLANS

Capacity Switch - Tube powered Motion Control 1950 How-To build PLANS

“How To Make Solenoids” 1935 HowTo PLANS Info Plunger Magnets A.C-D.C.

BUILD YOUR OWN VIBRATO Plans 1957 (2 TUBE CIRCUIT) AMP GUITAR AMPLIFIER FENDER

Photoelectric Pistol & Target 1948 HowTo build PLANS Tube Powered

Electric Lie Detector One Tube powered 1940 HowTo PLANS

*Quiz Party Guest w/ Double-Action Lie Detector" 1936 Vintage HowTo Build PLANS