Understanding Voltage Ratio
The voltage ratio Vo/Vs tells how much of a source signal reaches the output. It is also called voltage gain. A ratio above one means gain. A ratio below one means attenuation. A negative ratio means the output is inverted. This calculator supports measured values, resistor dividers, loaded dividers, and common amplifier gains. It also gives decibel gain, percent transfer, and reciprocal loss.
Why The Ratio Matters
Designers use this ratio to check filters, sensors, bias networks, and amplifier stages. A small ratio can protect an input. A large ratio can boost a weak sensor signal. The same number also helps compare measured circuit behavior with expected theory. When the result differs, wiring, loading, tolerances, or measurement range may be wrong.
Direct Measurement Method
For a direct test, enter the source voltage and output voltage. Use peak, RMS, or DC values consistently. Do not mix peak input with RMS output. The calculator converts selected units before division. It then reports Vo/Vs, Vo as a percentage of Vs, and gain in decibels. This gives a fast view of signal transfer.
Divider And Load Method
A basic divider uses two resistors. The lower resistor sets the output fraction. A real circuit often adds a load. That load sits in parallel with the lower resistor. The effective lower resistance becomes smaller. The output ratio usually falls. This tool includes that effect when loaded divider mode is selected.
Amplifier Gain Method
Op amp stages can be checked quickly. An inverting stage uses negative feedback gain. Its sign shows phase reversal. A non-inverting stage adds one to the feedback ratio. Always confirm that the output voltage stays inside the supply rails. Real amplifiers also have bandwidth, slew rate, and offset limits.
Practical Tips
Use accurate values for resistors and voltages. Choose units before calculating. Check the decibel result when comparing audio, RF, or filter stages. Export results when you need a record. Treat the result as an ideal estimate unless all parasitic effects are known. For high frequency circuits, include source resistance, cable loss, and probe loading in your review. Save each calculation with notes. This helps teams compare simulations, bench readings, and revised component choices during later design reviews with evidence.