Can someone help me identify a circa 1930-40s(?) device I picked up on e-bay? I bought it because I thought it was some sort of field strength meter. Nope.
Description is: ID plate on bottom reads "Pilot Products Company, Salt Lake City, Utah - Chicago, ILL., Input 115v, 50-60 cycles, Max.Current 15 Amps, Model PBBY Ser No. 2830, Patent No. 2,235,895". The enclosure is bakelite, painted in a creme white paint, size is about 9x9x8 in inches, Has the words in raised lettering "Radio Wave" in a stylistic print which resembles a lightening bolt. Unit has two indicator lights, one with a red bezel, one with a green bezel. There is a rotary switch on the front marked in selections " OFF-ON-FINE-MED-COARSE". Has a 2 inch meter in the front marked 0-50 in increments of 10, without units indicated (watts, amps, etc). Inside the case appears to be a relay, a transformer, a round selenium rectifier (I think)and something that plugs into a 5 pin tube socket. This tube device has stamped into its aluminum cover: SIGMA INSTRUMENTS 3271. Might be a vibrator? The main enclosure has three standard 2-conductor ac cord line wires, one for plugging into wall AC, a second is a female connector for a reg. 115v male plug, and the third is split with each side having an alligator clip. What is this thing??? I can e-mail a jpeg to anyone needing a picture.

: Can someone help me identify a circa 1930-40s(?) device I picked up on e-bay? I bought it because I thought it was some sort of field strength meter. Nope.
: Description is: ID plate on bottom reads "Pilot Products Company, Salt Lake City, Utah - Chicago, ILL., Input 115v, 50-60 cycles, Max.Current 15 Amps, Model PBBY Ser No. 2830, Patent No. 2,235,895".

You can get a reprint of the patent from the US Patent Office. Most likely this patent describes an invention which is related to the piece of equipment you have bought.
Gidi Verheijen

: : Can someone help me identify a circa 1930-40s(?) device I picked up on e-bay? I bought it because I thought it was some sort of field strength meter.

Yuk yuk: It's a permanent hair waving device. It controls the applied heat by sensing the conductivity of the hair. 1941.