RF Unit Converter

Convert between RF units for voltage, power, and current in radio frequency circuits

RF Unit Conversion Calculator

Ω

Typical values: 50Ω, 75Ω, 300Ω

Enter voltage in your preferred unit

Conversion Results

0.7071
V (RMS)
Output Voltage
10.0000
mW
Output Power

Formulas used: P = V²/Z, I = V/Z (where V is RMS voltage)

Input (RMS): 0.7071 V, Impedance: 50 Ω

Conversion note: Peak voltage = RMS × √2, dBμV = 20×log₁₀(V×10⁶)

RF Unit Reference

Voltage Units:
  • • V (peak): Peak voltage
  • • V (RMS): Root mean square voltage
  • • μV (RMS): Microvolts RMS
  • • dBμV: Decibels above 1 microvolt
Power Units:
  • • W: Watts
  • • mW: Milliwatts (10⁻³ W)
  • • μW: Microwatts (10⁻⁶ W)
  • • dBm: Decibels above 1 milliwatt
  • • dBμW: Decibels above 1 microwatt

Example Calculation

50Ω System Example

Given: 1V peak signal, 50Ω impedance

RMS Voltage: 1V ÷ √2 = 0.7071V

Power: (0.7071V)² ÷ 50Ω = 0.01W = 10mW

Current: 0.7071V ÷ 50Ω = 14.14mA

dBμV Conversion

0.7071V RMS = 707,100μV RMS

dBμV = 20 × log₁₀(707,100) = 117.0 dBμV

Common RF Impedances

Coaxial Cable (RG-58)50Ω
TV/Video (RG-59)75Ω
Twin Lead300Ω
Microstrip PCB50-100Ω

Key Formulas

Ohm's Law
V = I × R
Power
P = V² / R = I × V
Peak to RMS
V_rms = V_peak / √2
dB Conversion
dB = 20×log₁₀(V/V_ref)

RF Circuit Tips

Match impedances to minimize reflections

Use RMS values for power calculations

dBm is referenced to 1 milliwatt

50Ω is standard for most RF systems

Understanding RF Units and Conversions

AC vs DC in RF Systems

RF (Radio Frequency) circuits use alternating current (AC) where voltage and current constantly change direction. This requires different measurement approaches compared to DC circuits.

RMS vs Peak Voltage

  • Peak Voltage: Maximum instantaneous voltage
  • RMS Voltage: Effective voltage for power calculations
  • Relationship: V_rms = V_peak ÷ √2 ≈ V_peak × 0.707

Decibel Units (dB)

Decibel units provide a logarithmic scale useful for RF measurements where values can span many orders of magnitude.

dBμV (Voltage)
dBμV = 20 × log₁₀(V / 1μV)
dBm (Power)
dBm = 10 × log₁₀(P / 1mW)
dBμW (Power)
dBμW = 10 × log₁₀(P / 1μW)

Impedance Matching

Impedance matching is crucial in RF systems to ensure maximum power transfer and minimize signal reflections.

  • Mismatched impedances cause signal reflections
  • Standing waves reduce power transfer efficiency
  • Perfect match occurs when source = load impedance

Standard Impedances

50Ω: Most RF equipment, test instruments

75Ω: Video, cable TV, some antennas

300Ω: Twin-lead transmission lines

377Ω: Free space impedance