Duo 773 Electrometer

Headstage

For intracellular dual or differential studies, the Duo773 has separate negative capacity controls and built-in active filtering that allows the precise balancing of time constants for artifact-free differential measurement. Comes complete with two probe headstages, 10^15 Ohms & 10^11 Ohms probes to monitor signals from ion-specific micro-electrodes as well as KCl-filled electrodes. Two gold-plated, epoxy sealed miniature active probes can be positioned directly to the measurement site. Microelectrode holders containing an Ag/AgCl electrochemical half-cells plug directly into the probes. Stray capacitance can be reduced by placing the included driven guard shield over the microelectrode holder at the end of the probe.

Capacity Compensation

Channel A can compensate up to 10 pF of electrode shunt capacity and Channel B can compensate up to 50 pF.

Tickler Circuit

Assists in cell penetration. The frequency and amplitude of the oscillations may be varied for differences in membrane thickness or cell size. The duration of tickle can be controlled either by using the momentary switch, a foot switch, or by applying a signal to the remote tickler input.

Active Filters

Low pass settings on a -40 dB/decade active filter vary the cutoff from 1 to 30 kHz. Either probe or bridge outputs may be selected for filtering.

Current Injection

Channel B can eject current through the microelectrode by applying a command signal to the stimulus input connector; the resulting output from the probe will then be a constant current replica of the input signal. Two ranges of current delivery are provided: 50 nA and 500 nA or by an external source. This source can be useful for delivering hyperpolarizing currents to stabilize the cell membrane potential and as a holding current for microiontophoresis.

Bridge Balance

Subtracts the excess electrode voltage associated with delivering current through the recording micropipette. Electrode resistances up to 1000 MΩ can be balanced in two ranges. The balanced signal is available from x10 or x50 front panel output connectors.

Independent Outputs

The Duo773 has an output for each probe independent of gain filtering or balancing. In addition the Duo773 has a 10x and a 50x output for easy integration to most data aquisition programs.

HEADSTAGE (PROBE)	712P (red, port B), 715P (blue, port A)
ACTIVE PROBE INPUT IMPEDANCE 712P (red, port B)	>10^11ohm
ACTIVE PROBE INPUT IMPEDANCE 715P (blue, port A)	10^15ohm
GAIN 712P (red, port B)	x1, x10
GAIN 715P (blue, port A)	x1
OUTPUT RESISTANCE 712P (red, port B)	100ohm
OUTPUT RESISTANCE (blue, port A)	100ohm
OUTPUT VOLTAGE RANGE 712P (red, port B)	±10 V
OUTPUT VOLTAGE RANGE (blue, port A)	± 10V
MAXIMUM INPUT VOLTAGE 712P (red, port B)	±15V
MAXIMUM INPUT VOLTAGE (blue, port A)	±15 V
PROBE LEAKAGE CURRENT 712P (red, port B)	5 X 10-12 A
PROBE LEAKAGE CURRENT (blue, port A)	10-14 A
DC POSITION ADJUST RANGE 712P (red, port B)	± 300 mV
DC POSITION ADJUST RANGE (blue, port A)	± 300 mV
ELECTRODE RESISTANCE TEST CURRENT 712P (red, port B)	1nA
ELECTRODE RESISTANCE TEST CURRENT (blue, port A)	1pA, 1nA selectable
INPUT CAPACITY COMPENSATION 712P (red, port B)	+10 to -50Pf
INPUT CAPACITY COMPENSATION (blue, port A)	0 to -10pF
NOISE:Input shorted 712P (red, port B)	<50uV p-p 10kHz bandwidth
NOISE:Input shorted (blue, port A)	<50uV p-p 10kHz bandwidth
NOISE:20 MĪ© carbon resistor 712P (red, port B)	<200uV p-p 10kHz bandwidth
NOISE:20 MĪ© carbon resistor (blue, port A)	<200uV p-p 10kHz bandwidth
RISE TIME:10-90% direct input small signal	1us, typical
RISE TIME:10-90% through 20MOhm (-C "on")	25us, typical
CURRENT INJECTION: Internal DC Current 712P (red, port B)	± 50nA low range, ± 500nA high range
CURRENT INJECTION: Externally commanded Current 712P (red, port B)	± 500nA low range, ±5uA high range
CURRENT INJECTION: External current command factor 712P (red, port B)	20mV/nA low range, 2mV/nA high range
CURRENT INJECTION: Current monitor 712P (red, port B)	100mV/nA low range, 10mV/nA high range
CURRENT INJECTION: Compliance 712P (red, port B)	3V low range, 10V high range
CURRENT INJECTION: Bridge balance 712P (red, port B)	0-100ohm, 0-1000ohm
CURRENT INJECTION: Bridge amplifier gain 712P (red, port ā€œBā€)	x 10, x 50
LOW PASS FILTER	40 dB/decade, continuously variable 1-30 kHz
METER SECTION: Display	3.5-digit LED
METER SECTION: Ranges	200 mV, 2000 mV, 20 V, 200 nA, 2000 nA
METER SECTION: Accuracy and resolution	1 digit
DIMENSIONS: Instrument	17 x 5.25 x 10 in. (43 x 13 x 25 cm)
DIMENSIONS: Probe	Diameter: 12 mm Length: 34mm
POWER	95-135V or 220-240V, 50/60Hz
SHIPPING WEIGHT	15 lb (7 kg)
CERTIFICATION	CE, CSA

DUO773 Instruction Manual

Y. Ohta, M.E. Alojado, O. Kemmotsu "Activity changes in rat raphe magnus neurons at different concentrations of fentanyl in vitro" Anesthesia & Analgesia 80. 1995: 890-895

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Customers from North America can order direct from our corporate office:
World Precision Instruments
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Sarasota, FL 34240-9258

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712P	Replacement probe (includes calibration)
715P	Replacement probe (includes calibration)
2933	Rack Mount kit
2547	Driven Guard Shield
15790	Replacement Probe Handle
TW100F-4	Glass capillary with filament
TW150F-4	Glass capillary with filament

No application notes are available for this product at this time.