General view of electromagnet form of Duddell moving-coil oscillograph, showing the oil bath, and electromagnet.
This instrument is specially designed to have a very high natural period of vibration (about 1 / 10,000 of a second) so as to be suitable for accurate research work. It is quite accurate for frequencies up to 300 Hz.
In the figure:
A is the brass oil bath in which two vibrators are fixed
B, core of electromagnet which is excited by two coils
C, one of the two coils
D, two pairs of terminals for connecting the two coils
E, bolts that hold the oil bath in position between the poles of the magnet
F, two of three leveling screens (one is hidden behind the oil bath)
=== Illustration Description === Figure 2607 -- Duddell Moving Coil Oscilliograph General view of electromagnet form of Duddell moving-coil oscillograph, showing the oil bath, and electromagnet. This instrument is specially designed to have a very high