Dps2A - Power Supply - Wavetek 3000 Instruction Manual

THEORY OF OPERATION
The two internal oscillators are ampli-
fied/leveled
by the same circuit
for
simplicity but separately
energized by
the FREQ switch .
The oscillators are
twin T oscillators, one is at 400 Hz the
other is at 1 kHz .
3 .4 .2 Accuracy Lights
Which LEDs are lit is determined by the
MODE switch . If any of the phase locked
loops unlock, the energized LEDs are
made to flash by an IC timer which is
activated by a DC level from any of the
four phase locked loops in the instru-
ment .
3 .5
DPS2A - POWER SUPPLY
The DPS2 provides DC power for the rest
of the instrument . See Figure 3-10 .
3 .5 .1 Transformer & Filters
The transformer steps down the line vol-
tage to appropriate levels for the three
circuits . Full wave rectifiers and
filter capacitors convert this voltage
to DC .
3-10
AC
L lNE
3 .5 .2 +18 V SUPPLY
The +18 V circuit has a temperature-
compensated precision voltage reference .
This reference iscompared to the output
voltage by an error amplifier
which
corrects any error in the output voltage .
3 .5 .3 -18 V SUPPLY
The -18 V circuit compares the + .18 V and
-18 V outputs and holds the difference
in their magnitudes to zero .
3 .5 .4 +7 .3 V SUPPLY
The +7 .3 V circuit uses. a three-terminal
adjustable voltage regulator IC to pro-
vide a pre-regulated i-7 .3 V output .
This voltage supplies other voltage
regulators throughout the instrument .
Figure 3-10 . DPS2 - Power Supply .
4 /8 voc rs
- lB voc rs
-f- 7 . 3 vo c rs