Channel Conductance Guide
What Conductance Means
Channel conductance describes how easily charge moves through a channel. It is often used for ion channels, pores, membranes, and simplified circuit paths. A higher value means current passes more easily. A lower value means the channel resists flow.
Main Calculation Idea
This calculator uses current, membrane voltage, and reversal potential. The difference between voltage and reversal potential is the driving force. Current divided by driving force gives conductance. With picoamps and millivolts, the answer is directly in nanosiemens.
Resistance and Open Channels
The tool also estimates resistance, because conductance and resistance are opposites. Resistance helps users compare channels with familiar circuit terms. It can show whether a path is highly open, partly open, or almost closed. For channel groups, the calculator can include channel count and open probability. This gives single channel conductance and current per open channel.
Geometry Estimate
Advanced users may also enter radius, length, and solution conductivity. These values create a simple geometric estimate. It assumes a cylindrical channel. It is not a full biological model. It is useful for quick comparisons and teaching. Differences between electrical and geometric conductance can suggest gating, selectivity, measurement error, or missing assumptions.
Good Unit Practice
Use careful units for best results. Current should be entered in picoamps. Voltage and reversal potential should be in millivolts. Radius and length should be in nanometres. Conductivity should be in siemens per metre. A zero driving force cannot produce a stable conductance value, because the formula would divide by zero.
Result Review
The result area appears above the form after submission. It gives total conductance, signed conductance, resistance, driving force, and optional channel estimates. The downloadable files help keep records. The example table gives sample values for common scenarios.
Practical Use
This calculator is made for learning, planning, and quick checks. It cannot replace laboratory analysis. Real channels may have nonlinear current voltage curves, rectification, noise, and concentration effects. Still, the basic conductance formula is a strong first step. It helps users understand flow quickly. It also supports clean comparisons between experiments, devices, membranes, and channel models.
Design Insight
For design tasks, it can estimate how changing size affects flow. Wider pores increase area. Longer pores reduce conductance. Higher conductivity raises conductance. These trends are simple, but they guide early choices before deeper simulation or measurement begins and saves review time.