3B SCIENTIFIC PHYSICS 1017781 Manual De Instrucciones página 6

2. Description
The charge and discharge apparatus is designed
for recording points along a charging and dis-
charging curve for three built-in resistor-capacitor
pairings or similar external pairings. It can also be
used to determine the values of the resistors and
capacitors used. The equipment consists of a volt-
age comparator, a digital counter for measuring
the charging or discharging time and three internal
resistor-capacitor pairs.
The voltage comparator compares the charging or
discharging voltage across the capacitor with a
reference voltage, which can be pre-set to any of
11 levels from 0.5 V to 9.5 V.
Once the function switch is set to START-
CHARGE or DISCHARGE, the digital counter
starts counting until the set reference voltage is
reached, at which point it stops. Prior to this, the
digital counter is set to zero by means of the RE-
SET button. If it is not reset, the counter works by
adding times together.
Three RC pairs can be formed from the three built-
in resistors and the internal capacitor, selected via
INTERN 1, INTERN 2 and INTERN 3. There is
also an EXTERN setting which connects the volt-
age comparator to the terminals for external resis-
tors and capacitors.
Charge and discharge apparatus 1017781 is pro-
vided with a plug-in power supply for 230 V
(±10%), whereas model 1017780 has one for
115 V (±10%).
3. Technical data
Internal capacitor:
Internal resistors:
Voltage U :
0
Digital counter:
Maximum time:
Resolution:
Power supply:
Dimensions:
Weight (incl. power supply)
2000 μF ±10%
2.2 kΩ, 5.1 kΩ, 10 kΩ
10 V
4-digit, quartz-controlled,
1 place of decimal
200 s
100 ms
Plug-in supply, 12 V AC,
2000 mA
260 x 220 x 55 mm
1700 g
4. Accessories
For carrying out measurements on external resis-
tors and capacitors, the following plug-in compo-
nents are recommended:
Capacitor, 1000 µF
Resistor, 4.7 kΩ
Resistor, 10 kΩ
Resistor, 22 kΩ
5. General instructions
When the selector switch is set to INTERN 1, IN-
TERN 2 or INTERN 3, the internal capacitor will be
connected to the terminals used for an external ca-
pacitor.

Do not connect an external capacitor when carry-
ing out measurements on the internal RC pairs.
The charging and discharging times measured are
affected by bounce periods, which can be made
worse if the charge/discharge switch is turned ten-
tatively.

Always turn the switch quickly.

To determine the time more accurately, it may
be advisable to carry out each measurement
at least three times and take the average.

Only choose external RC pairings which have
a time constant
6. Operation
6.1 Turning on

Connect the charge and discharge apparatus to
the mains via the plug-in power supply provided.
6.2 Measurements on internal resistor-capac-
itor pairs

Remove any external resistors or capacitors.

Set the selector knob to INTERN 1, INTERN 2
or INTERN 3.
6.3 Measurements on external resistor-capac-
itor pairs

Plug an external resistor and capacitor into the
relevant terminals.

Set the selector knob to EXTERN.
2
1017806
1012920
1012922
1012924
 
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R C 4 s