Plücker Tubes.
A special form of Geissler tube designed for the production of
stratification and for observing the effects produced in the space
surrounding the negative electrode.
Plug.
(a) A piece of metal with a handle and a somewhat tapered end, used to
make connections by insertions between two plates or blocks of metal
slightly separated and with grooves to receive it.
(b) A plug or wedge with two metallic faces, insulated from each other
with a separate wire connected to each one. It is used in spring-jacks
q. v., to introduce a loop in a circuit.
Synonym--Wedge.
Plug. v.
To connect by inserting a plug, as in a resistance box.
Fig. 265. PLUGS FOR RESISTANCE COIL BOX.
Fig. 266. PLUG SWITCH.
Plug, Double.
A spring-jack plug or wedge with two pairs of insulated faces, one
behind the other, so as to simultaneously introduce two loops into a
circuit.
Plug, Grid.
A piece or mass of lead oxide, inserted into the holes in the lead
plates of storage batteries. The holes are often dovetailed or of uneven
section to better retain the plugs.
Plug Infinity.
In a box-bridge or resistance box, a plug whose removal from between two
disconnected discs opens the circuit. All the other discs are connected
by resistance coils of various resistance.
Plug Switch.
A switch composed of two contact blocks, not touching each other and
brought into electrical connection by the insertion of a metallic plug.
The latter is usually provided with an insulating handle, and a seat is
reamed out for it in the two faces of the contact blocks.