Posted 5 years ago
This Edison Mazda bulb operates on 220 volts. It has a 3 loop filament. It still lights up when connected to 115 volts but at half brilliance. The 115 v bulbs have 2 loops . I have 2 of the 115 v which still work with wrappers.
In the filament support tube there is a paper insert that has 5 patd dates. The latest is Apr 28 03.
I found these at an Academy Military Surplus (?) store in the early 50's when Academy was dealing in surplus. I purchased 9 bulbs,some 115 v and 220v types.
There was a large box full but I only purchased 9. Some in the original yellow wrapper. Most have been sold at auction.
Going by the patd date the bulb is 109 years old