Simple JavaScript tools with minimal input error checking
A. Calculate 2 Resistor Voltage Divider Bias
Enter Voltage:
Enter R1:
Enter R2:
Bias voltage
=
B. Calculate Inductive
Reactance
Enter Inductance in uH:
Enter Freq in MHz:
XL (ohms) =
C. Calculate # of Turns To
Obtain a Desired Inductance on a Ferrite Toroid
Enter Inductance in millihenries:
Select Core:
Turns
=
The AL for this ferrite core is =
D. Calculate Cut off
Frequency for an RC Pi Low-Pass Filter
Enter resistor value in ohms:
Select capacitor values in uF:
3 dB down frequency (Hertz) =
E. Calculate Power in dBm
and mW from Peak-to-Peak Voltage
Enter measured peak-to-peak voltage into a 50 ohm load:
dBm, mW
Application Note: This web site follows the EMRFD standard
for dBm power measurement. dBm = the power delivered into a 50 Ohm resistive
load which is temporarily substituted at that point in the signal chain.
F. Calculate Lm and Cm For a Crystal using the
G3UUR Method
Enter frequency in MHz written on crystal
(series resonant frequency):
Enter measured frequency in MHz with switch open:
Enter measured frequency in MHz with switch thrown:
Enter crystal capacitance in pF:
Enter open switch circuit capacitance in pF:
Cm
= femto Farads ,
Lm =
Henries
G. Calculate Decibel Power Gain or Loss from 2
Peak-Peak Voltages
Enter voltage 1:
Enter voltage 2
dB
gain or loss =
H. Calculate Decibel Power Gain or Loss from
Input and Output Power
Enter input power in watts:
Enter output power in watts
dB
gain or loss =
I. Calculate dBm and mW from RMS Voltage (50
ohms)
Enter RMS voltage
dBm
mW
J. Calculate Return Loss and VSWR (50 Ohms
Detector)
Enter the detector signal in pk-pk volts when the unknown
port is terminated in an open circuit:
Enter the detector signal in pk-pk volts with the ? impedance connected:
Return loss
= dB, VSWR=1:
Measurements per Figure 7.41 EMRFD.
K. Calculate Power from the DC Output of an AD8307 Meter
1. Linear calibration steps:
Enter measured DVM voltage at -10 dBm:
Enter measured DVM voltage at -20 dBm:
2. Calculate power in dBm from DVM voltage:
Enter measured DVM voltage:
Power
=
L. L-C-C Tee Network
Enter frequency in MHz:
Enter R1 in Ω:
Enter
R2 in Ω:
R1 must be
< R2, but the network is bi-directional
Enter Q:
Perhaps start with 2-5
C1 = pF, C2 =
pF, L = uH
M. Parallel Resistor Values
(2-4 resistors) [ also may use for series caps etc. ]
Enter R1: Enter
R2 Enter R3:
Enter R4:
R = ohms
N. LCR -- a Reactance Calculator
In beta -- do not use !
Mode:
Inductance:
Enter frequency in MHz
