Sonotone "Voltmeter" Battery Tester (for Carbon Hearing Aids)
This Sonotone battery meter was made by the Sonotone Corporation of
Elmsford, NY.
It was used for testing the voltages of Sonotone 3 volt and 4˝
volt batteries commonly used in carbon hearing aids made in the 1920s
and 1930s.
To use it, you plugged it into the battery in question. The Sonotone batteries
of that day had pin sockets. For example, the
Sonotone X65
was one such battery.
|
|
Click picture for larger view |
|
|
|
|