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 Monday, 12 November 2018 3285 users online

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Formulas:

Vout = Vin * R1 /(R1+R2)

Vin = Voltage input
Vout = Voltageoutput
R1 = series resistor
R2 = shunt resistor

The total resistance of the attenuator is: R1 + R2
Thate does not include any impedance after the attenuator.

To calculate the total impedance including the load on the output, calculate the parallel resistance of the load and R2, add this to the value of R1.

Example:
R1 = 50.000 ohms
R2 = 100 ohms

Rparallel = (100 * 50000 ) / (100 + 50000) = 99.8 ohms
Rtotal = R1 + Rparallel = 49900,2 ohms

Converting a voltage to decibels: 20 * log(n)

where n = the voltage or resistance ratio.

Example:
R1 = 50000 ohms
R2 = 100 ohms

Rtotal ( R1 + R2 ) = 50100 ohms

dB = 20 * log(R2/Rtotal)

dB = 20 * log(100/50100) = -53.99dB

 Total Resistance (Rt): Ohms

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# Search closest standard resistor value

 E6: 20% resistors E12: 10% resistors E24: 5% resistors E48: 2% resistors E96: 1% resistors E192: 0.5%, 0.25%, 0.1% resistors

 Fill the desired value in, the closest standard value are shown in the different E serials: ohms

 EIA Serie closest value deviation, compared with theoretical value min/max value E6 E12 E24 E48 E96 (recommended) E192