Stimulus Isolator BVISO100 for Artifact Minimization

Stimulus isolator is an essential device for achieving electrical isolation in electrophysiology experiments.

Prevention of Interference with Recording Systems

In non-isolated stimulus devices, stimulus current flows through the entire solution or via ground electrodes, causing voltage increases in the chamber solution. This phenomenon makes accurate measurement of the target cell membrane potential difficult.

Control of Current Pathways

Non-isolated stimulus devices may allow current to flow through unexpected pathways within biological tissue, creating risks of unintended stimulation at unwanted sites.

Input Functions: Support for Both Analog and Pulse

The BVISO100 supports both analog input and 2-channel pulse input to meet the needs of electrophysiology experiments. These inputs are isolated through optical isolators and transmitted to subsequent signal processing sections.

Input mode switching can be easily performed with the "Input Mode" switch on the front panel.

Analog Input

Provides the function to isolate low-voltage signals (±1V or ±5V) and linearly amplify them to high voltage (±100V). The BVISO100 can be utilized as a linear isolator.

While it incorporates feedback circuits for improved linearity, approximately ±2% error exists.

When using analog input, operation is possible without dedicated software, supporting standalone operation.

Pulse Input (2 channels)

Converts TTL-level digital signals (0V/5V, threshold 1.4V) to arbitrary high-voltage pulse outputs. It features two independent channels: Pulse1 and Pulse2.

When using pulse input mode, USB connection to a PC and configuration with dedicated software are required. The pulse height (voltage or current) for each channel is set through software.

Output Functions: Voltage/Current Switching Capability

Voltage output and current output can be switched according to experimental conditions.

Switching is performed using the "Mode" switch on the front panel or the "Mode" button in the software.

Voltage Output (CV Mode)

Function to output voltage corresponding to input at a constant level regardless of load resistance. Output voltage range is ±100V, with current limited to a maximum of 3mA.

Current Output (CC Mode)

Function to output constant current, with voltage changing according to load resistance. Output current range is 0-1mA, with three selectable ranges: 1.0mA, 0.3mA, and 0.1mA.

Advanced Automatic Calibration Functions

The BVISO100 incorporates advanced automatic calibration functions to improve experimental accuracy and reliability.

It automatically compensates for problems caused by internal circuit variations and electrode characteristic changes, providing stable stimulus output and measurement environment.

Automatic Zero Calibration

Used primarily for the following purposes:

• Offset correction:
  Automatically adjusts offsets generated by temperature changes in internal circuits, maintaining output at zero
• Response to electrode polarization voltage:
  In voltage output mode, zero calibration with output ON executes offset adjustment matched to the fixed potential difference of electrodes, canceling fixed potential differences when using dissimilar metal electrodes and suppressing steady current flow

Execution can be initiated with the "Calibration - Zero" button on the front panel or the "AutoZero" button in the dedicated software.

Automatic Capacitance Calibration

Aims to provide phase compensation for delays caused by electrode resistance and maintain fast rise times of output pulses.

Can be executed with the "Calibration - Capacitance" button on the front panel or the "Cap.Comp" button in the dedicated software.

Capacitance Balance Adjustment Function

Function to cancel capacitive current caused by capacitance between the isolated section and ground. It minimizes artifacts from electrical stimulation and achieves high-precision electrode recording.

This function is not automatic adjustment but a manual adjustment method that observes artifacts appearing in recording electrode waveforms.

Real-time Monitoring of Output Voltage and Current

The system incorporates functions to monitor output voltage and current in real-time during electrophysiology experiments. Detailed waveform observation and numerical data confirmation are possible through main unit LED display and dedicated software.

This enables immediate understanding of stimulation conditions and rapid response when problems occur.

Additionally, by recording monitored voltage and current values, experiments can be conducted under highly reproducible stimulus conditions based on numerical values rather than relying on intuition from subsequent experiments.

Monitor Function Overview

• Main unit LED display:
  LEDs on the BVISO100 main unit display output voltage and current status
• PC waveform observation and measurement data display:
  Connect to PC via USB interface and observe output waveforms in detail on dedicated software

Dedicated Software Functions

Dedicated software is included that enables visual understanding of detailed stimulation conditions and saves measurement data.