Headstage—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. Compliance Alarm — When the electrode voltage exceeds the probe input maximum allowed voltage, an audible over-compliance alarm will sound. 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. Digital Meter — The Duo773 comes complete with a 3½-digit display for monitoring injection current or the voltages for either probe (single ended or differential). SYS-773 $ Duo 773 Electrometer 4,730 Specify line voltage Includes two probes (712P and 715P or two 712P) with driven guard shields and eight MEH1SF microelectrode holders for 1.0 mm, 1.2 mm, 1.5 mm, or 2.0 mm glass electrodes. OPTIONAL ACCESSORIES $ 712P Replacement probe (includes calibration)* 572 $ 715P Replacement probe (includes calibration)* 636 *Instrument should be returned to WPI for free calibration with new probe. 2933 2547 15790 TW100F-4 TW150F-4 Rack Mount Kit, 51⁄4-in. high Driven Guard Shield for 712P & 715P Probes Replacement Probe Handle Glass capillary with filament Glass capillary with filament See Dri-Ref, page 63. See cables and connectors, page 98. $ 114 $ 28 $ 72 $ 54 $ 54 AMPLIFIERS, ELECTROMETERS #2547 Driven Guard Shield Typical setup: Duo773 Optional Holders for Intracellular Amplifiers 50x gain output M EH F 1S (su pp lie d) Data Acquisition System M EH 2S F M EH 2S FW Recording Electrode (with holder MEH1SF) Drug or dye current electrophoresis injection M EH 3S F M EH 3S FW M EH 6S F Micromanipulator Micromanipulator M EH 6S FW Inverted Microscope See Microelectrode Holders, page 106 ORDER TOLL-FREE: 866-606-1974 (U.S. only) World Precision Instruments • Tel: 941-371-1003 • Fax: 941-377-5428 • E-mail: sales@wpiinc.com • Internet: www.wpiinc.com 71