_
EXPERIMENT 1—1. (e)
15
full-wave rectiertube, the iron core choke coil and the electrolytic
condensers serve to lter out voltage uctuations, the 25,000 ohm
10
watt
“
bleeder
”
resistance serves
to
regulate the output
voltage and the 0—100,000 ohm variable resistor serves to change
'
this voltage. The latter is accomplished, in this case, by means
.
of the variable ir drop of the current to the voltmeter V of gure
_
1—3.
The transformer T may also have one or more low voltage
secondaries which areused to light the ash lamp. The author
has found it advisable to overload the ordinary ash lamps in ‘
order to obtain better illumination, at a cost of shortened life of
the lamps. If the lamp is too large the heat is eXcessive, an
"…
Î.
-—
'
u
41
……
°coum,r
’FIG. 1—4.
A convenient Voltage supply.
’
‘
absorbing water cell is needed and the apparatus becomes more“
,
complicated. A high resistance voltmeter (0—250 volt, 1000 ohms
'
per volt) serv”es‘nicely to measure/7 .
…
'
'
-
ÂaÏiusz‘meîs.—l; Turn the ash lamp to one side and adjùst
.
its position or f0cus untila bright spot ‘ab0ut two millimeters in
j
Seen
located at the same distance
’
?
as
of thefcondenSen
-.
T'
;
,
_
‘
'
‘
_
Itt.-s..sh0uldàrfjus
.
=
Paint the
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swpeshouldpomtwwardthedarkœmerrïandthehnesof1ts
,S°0pelschangeduntllthebackr@u®fhghtJustperm1tsthe