I found this ad from 75 years ago to be intriguing. It’s an inverter for running 120 volt appliances from a car’s electrical system, presumably six volts. The ad appeared in the June 1946 issue of Radio Retailing.

I haven’t found much information about this unit, model 6-1160,  But it’s almost certainly vibrator driven.  The electromechanical vibrator changes the DC to a square wave, which is stepped up by a transformer.  It’s billed as providing up to 40 watts.

It’s priced at $15.95.  According to this inflation calculator, that works out to about $330 in 2021 dollars.  By comparison, a modern one such as the one shown here outperforms it and sells for just a few dollars.

The manufacturer, the Terado Company, appears to be defunct, but their street address jumped out at me.  I drive past it, 1068 Raymond Avenue, St. Paul, MN, almost every day.  There is currently an apartment building at that address, which I believe was built in the 1980s.

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