Understanding Gain
Gain describes how much a signal changes after passing through a device. The device may be an amplifier, sensor, filter, antenna stage, or control block. A gain value above one means the output is larger. A gain value below one means the output is reduced. A gain of one means the output matches the input.
Why Decibels Matter
Engineers often express gain in decibels. Decibels compress large ratios into smaller numbers. That makes reports easier to read. Voltage gain and current gain use twenty times the base ten logarithm. Power gain uses ten times the base ten logarithm. The difference exists because power follows a squared relationship in many systems.
Where This Calculator Helps
This calculator supports voltage, current, power, and percentage gain. You can compare measured input and output values. You can also convert common units before the ratio is found. This helps when one value is in millivolts and another is in volts. It also helps when power is entered as watts, milliwatts, kilowatts, dBm, or dBW.
Good Measurement Practice
Use stable readings before you calculate gain. Match the same signal point when possible. Use RMS values for AC voltage or current. Avoid mixing peak values with RMS values. For power, use positive values only. For negative voltage gain, the sign shows inversion. The decibel value still uses magnitude.
Reading the Result
The linear ratio shows direct multiplication. The decibel result shows logarithmic gain. The percentage result shows relative increase or decrease. A negative decibel value often means attenuation. A positive decibel value often means amplification. Zero decibels means unity gain.
Exporting Results
The CSV option is useful for spreadsheets. The PDF option is useful for quick records. Keep the notes field clear. Add the circuit name, test point, or load condition. Clear notes make later comparison easier. This is useful for labs, design reviews, audio tests, radio links, and troubleshooting work.
Design Tip
Always record the load impedance when power readings matter. A changed load can change the output level. Temperature, cable loss, supply voltage, and probe loading may affect results. Repeat tests and average stable readings. That improves confidence without making the method complex.