HP 4262A Operating And Service Manual page 51

Section III
Figure 3-8
Model 4262A
Extemnal DC Voltage Bias Circuits (40V< , < 200V)
1. Connect external dc bias source as shown in diagram.
CAUTION
DO NOT APPLY DC VOLTAGE EXCEEDING
200VOLTS OR 4262A CIRCUITRY WILL BE
DAMAGED.
DC POWER SUPPLY
aw (Vi)
A
Rl ES 200V
b © +O
E
00000000
-©—1_
Note
+E voltage is applied to Cx in figure. -E voltage
can be applied to Cx in this figure. In the above
arrangement, the polarity of Cx and C1 must
be taken into consideration.
CATUION
NEVER SHORT BETWEEN Hror AND LOW
TERMINALS WHEN R1 IS SMALLER THAN
1k2. MAKE SURE THAT UNKNOWN CAPA-
CITOR IS NOT DEFECTIVE BEFORE CON-
NECTING TO INSTURMENT.
TO AVOID HARMFUL SURGE CURRENT
WHICH MAY FLOW THROUGH INTERNAL
CIRCUITRY WHEN A HIGH VOLTAGE DC
BIAS IS SUDDENLY APPLIED, IT IS RECOM-
MENDED THAT DC BIAS BE GRADUALLY
INCREASED FROM A LOWER VOLTAGE.
Note
Ripple or noise of external dc bias source should
be as low as possible. The low frequency noise
of bias source should be less than 1mVrms for
a TEST SIGNAL level of 50mV (LOW LEVEL)
and 30mVrms for 1V.
Cx . Unknown capacitor
v/
3-20
Figure 3-9. External DC Bias Circuit (Sheet 1 of 3).