[Cw] sounder question?

[David J. Ring, Jr.]

Sounders ran off of 100-120 volt DC lines.  However they were in series with
large adjustable ballast resistors.

The voltage applied to them to operate varies depending on the value of the
coil resistance, some coils were 4 ohms, some 16, some much higher.

Search using www.google.com for "Morse Telegraph Club"; they have an archive
of different power supplies - I believe they usually use 60 volts, but again
they have ballast resistors to adjust for minimum operating current.

Try D cells arranged in a battery if you want, first try one D cell then try
2 D cells or 3 D cells to make higher battery voltage - the current will be
limited by the internal resistance of the D cells.

A 4 ohm sounder might work on a D cell, but if it is a higher resistance
coil, you might have to make a battery of D cells.  (A battery is by
definition a group of cells wired together.)  If you have a high resistance
(high impedance) sounder coil like in a "main line" sounder, you might try a
square 9 volt battery.

73

DR



----- Original Message ----- 
From: Mark Choate
To: CW
Sent: Monday, May 10, 2004 9:00 PM
Subject: [Cw] sounder question?


a friend of mine just recently aquired a sounder set up. what supply voltage
do these units take? he is afraid to plug it in to the 120vac recepticle as
he might smoke the thing.

any help?

Mark



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