Electronics Menu

This section covers the functions of the General Electronic Menu. Selecting the “Elec Calc” item from the menu accesses this set of basic electronics functions.

 

Ohms Law

Selecting this tab allows the user to perform various Ohms Law calculations. The basic V=IR and the variations of it as shown on the screen. In addition it also calculates wattage and Horse Power Hp. Any two parameters (V, I, R & W) can be input and the remainders are calculated. The Hp calculation uses the Watts and Efficiency to calculate. The default efficiency is 90%. Figure below shows a voltage of 120V and current of 6.5Amps and the Resistance and Wattage and Hp are all calculated. Press “Calculate” to perform, “Clear” to clear and start over and “Close” to quit the screen.

Figure 16 – Ohms Law

Resonance

Selecting this tab allows the user to make resonance calculations using any three of the four possible inputs ohms, inductance, capacitance and frequency. Figure 11 shows a resistance, inductance and capacitance input to calculate the resonant frequency, Q and series / parallel impedances shown in figure.

Figure 17 – Resonance

Inductance

Selecting this tab allows the user to make general inductance calculations of series and parallel inductance. The user can also select to determine the reactance impedance of an inductor value at a specific frequency.

 

Figure 18 – Inductance

Capacitance

Selecting this tab allows the user to make general capacitance calculations of series and parallel capacitance. The user can also select to determine the reactance impedance of a capacitor value at a specific frequency.

 

Figure 19 – Capacitance

 


Resistance

Selecting this tab allows the user to make general resistance calculations of series and parallel resistance and also Voltage Divider applications. Enter the R1 and R2 values in the Parallel and Series Resistance section and press the right Calculate to compute the Parallel and Series Resistances.

 

For the Voltage Divider application enter any three of the four input and press the Left Calculate and it will compute the missing member of the set. In addition is will also calculate the total current thru the voltage divider.  In the case shown in figure below, the input voltage is 28V and the voltage output desired is 5V and the upper resistor, which for the most part will determine the major resistance and determining the approximate current flow is 3K Ohms. This should give about 1mA of current. Indeed the calculated R2 value for the lower resistor is 652 Ohms with 1.369mA total unloaded divider current flow.

 

Figure 20 – Resistance Parallel and Series and Voltage Divider

 

Temperature/Distance

Selecting this tab allows the user to make general US and Metric distance calculations and also temperature conversions. User inputs any one value for either calculation and the others are computed for that selection.

Figure 21 – Temperature/Distance Conversion

 


Inductors

Selecting this tab allows the user to make inductor value estimates for Straight Wire, Straight Wire Offset from Ground and coil inductance. Input the wire radius in centimeters (cm) and the wire length in cm, then press the calculate Wire Inductance. If the Straight Wire from Ground calculation is desired, then add the Input Distance from Ground in cm and press the next Calculate Wire Inductance button. If the Coil Inductance is desired then input the Radius (cm), length of the coil and either the turns or the inductance. Whichever of the last two is input the other will be calculated when the Calculate Coil Inductance is pressed.

 

Figure 22 – Inductors Length, Radius, Inductance Input

Capacitors

Selecting this tab allows the user to Calculate Parallel Plate Capacitance, or Coaxial Cylinder capacitance. Input the Er – Dielectric Constant and either the Area and Distance (separation) or the Inner Diameter and Outer Diameter to calculate the respective Parallel Plate or Coaxial Cylinder Capacitance.

 

Figure 23 – Capacitors

 

Resistor Color

This selection allows the user to get the resistor colors or identifiers for inputs to values. The Resistor Color Bands are for 2, 5, 10 and 20% tolerance resistors. The numeric identifier is used for the 1% tolerance resistors. The pull down item “text box” inputs is fixed to the range of values available. The actual resistance value is shown in the Resistance Text Box output when calculated. Included in the calculations are the upper and lower bounds of the resistor value with the applied tolerance applied.

 

Figure 24 – Resistor Color

Filter

RC Low Pass

This screen calculates the 3dB low pass 3dB cut-off frequency. Enter the capacitance and resistance and press Calculate to compute and display. Clear to reset and reenter value to retry and Close to Quit.

 

Figure 25 – Filter RC Low pass


RL High Pass

This screen calculates the 3dB high pass 3dB cut-off frequency. Enter the inductance and resistance and press Calculate to compute and display. Clear to reset and reenter value to retry and Close to Quit.

Figure 26 – Filter RL High Pass

RLC Band Pass

 

Enter the R in Ohms, the inductance in Henries and the Capacitance in Farads and press Calculate to compute the resonant frequency, the Q and the Series and Parallel Impedance in Ohms of the circuits. Press Calculate to compute and display. Clear to reset and reenter value to retry and Close to Quit.

 

Figure 27 – Filter RLC Band Pass/Reject


Op Amp and Active Filter

Non Inverting Op Amp

Enter the input (generator) resistance and the feedback resistance and press Calculate to compute the voltage and dB gain for the amp. Press Clear to clear the values to re-enter.

 

Figure 28 – Non Inverting Op Amp

 

Inverting Op Amp

Enter the input (generator) resistance and the feedback resistance and press Calculate to compute the voltage and dB gain for the amp. Press Clear to clear the values to re-enter.

 

Figure 29 – Inverting Op Amp

 

Low Pass Active Filter

Enter the frequency for the low pass cut off frequency in Hz. Press the Calc button next to it to calculate the recommended Cref (C2) value. Select the desired C calc (C2) value from the drop down list of real values in pF, also the a (alpha value for the Butterworth filter section of the filer system desired. I chose 1st section of 2 (0.765). Finally add the gain value in voltage ratio desired. Press Calculate to compute the R1 thru R4 and C1 values for the active filter circuit. Press Clear to clear the values to re-enter.

Figure 30 – Op Amp – Low Pass Active Filter

High Pass Active Filter

Enter the frequency for the high pass cut off frequency in Hz. Press the Calc button next to it to calculate the recommended Cref (C) value. Select the desired C calc (C) value from the drop down list of real values in pF, also the a (alpha value for the Butterworth filter section of the filer system desired. I chose 1st section of 2 (0.765). Finally add the gain value in voltage ratio desired. Press Calculate to compute the R1 thru R4 values for the active filter circuit. Press Clear to clear the values to re-enter.

Figure 31 – Op Amps – High Pass Active Filter

 

Band Pass Active Filter

Enter the frequency for the band pass frequency in Hz, the filter Q value, the gain in voltage ratio. Select the desired C (C=C1=C2) value from the drop down list of real values in pF. Press Calculate to compute the R1 thru R3 values for the active filter circuit. Press Clear to clear the values to re-enter.

 

Figure 32 – Op Amp – Band pass Active Filter

 

Band Reject Active Filter

Enter the frequency for the band reject frequency in Hz, the R1 resistor value. Select the desired C2 value from the drop down list of real values in pF. Press Calculate to compute the R1 thru R3 values for the active filter circuit. Press Clear to clear the values to re-enter.

 

Figure 33 – Op Amp – Band Reject Active Filter

 


Resistivity

Resistivity

This screen helps the operator perform Resistivity calculations.  Enter the Area in Sq cm, Length in cm, Temperature, and Temp Coefficient. If the user selects the check box and the type of material predefined, then the Resistivity and Temp Coef will be filled in automatically for you. Then press “Calculate” to get the Resistance. Press “Clear” to clear the coefficients and begin over. Press “Close” to quit the screen and go back to main menu. The material list and coefficients are in the INI file and can be added to or modified. I have selected most used standard materials for initial inputs. I also added the feature of AC Resistance at a specified frequency. If the frequency is specified, then the AC resistance will be displayed.

 

Figure 34 - Resistivity

Skin Depth

This screen helps the operator perform Skin Depth calculations.  Enter the Conductivity and frequency of operation in Hz. If the user selects the check box and the type of material predefined, then the Conductivity will be filled in automatically for you. Then press “Calculate” to get the Skin Depth in cm. Press “Clear” to clear the coefficients and begin over. Press the “Close” button to quit the screen and go back to main menu. The material list and coefficients are in the INI file and can be added to or modified. I have selected most used standard materials for initial inputs.

Figure 35 – Skin Depth

 

Y-Delta Conversion

This screen helps the operator perform Y to/from Delta calculations.  Enter the three Delta or the three Wye resistances and press “Calculate” to get the conversion resistance equivalents. Press “Clear” to clear the resistances and begin over. Press the “Close” button to quit the screen and go back to main menu.

 

Figure 36 – Y-Delta conversions

 

Wire Resistance

This screen will perform he calculation for Wire Resistances. Use the pull down combo boxes to select the wire type or AWG and also the material type. Check the Check box to use the combo box selection inputs for Area, Resistivity and Temp Coef. Otherwise enter your own values. Also enter the Length and Temperature. Temperature will default to 25 deg C. Press and “Calculate” to get the wire resistance, press “Clear” to clear the fields and begin over. Press the “Close” button to quit the screen and go back to main menu.

 

Figure 37 – Wire Resistance


Wheatstone Bridge

This screen can compute the missing resistor value for a “ Balanced Bridge ” condition (V2=0). By entering three of the four resistor values and Press Calculate to compute and display. Clear to reset and reenter value to retry and Close to Quit.

.

Figure 38 – Wheatstone Bridge Resistances

 


Attenuation

Pi and Tee Attenuators

Selecting this tab will allow the user to make calculations for PI and Tee attenuators. The inputs are Loss in dB, Zin and Zout (input and output impedance). The user then selects “Calculate Pi” or “Calculate Tee” for the respective calculation. After this is performed the user can select to convert Tee to PI or PI to Tee if desired by pressing the respective button for the operation. The user can also select Clear all or Clear Attenuation) to rerun, without losing all the inputs.

 

Figure 39 – Attenuator PI<>Tee

 

 

Min Loss Attenuation

Selecting this option the user can enter an Input Impedance ZIn and an Output Impedance Zout and calculate the parallel and series resistor value that will make a minimum loss attenuator for a match between line of different impedances (i.e. 50 to 75 Ohms or 75 to 300 Ohms-Cable to TV) It also calculates the loss factor in decibels (dB). Note: ZIn must be greater than ZOut! The two resistor values are the series and parallel resistance

 

Figure 40 – Attenuator  Minimum Loss

 

Un-Equal Divider

Selecting this option the user can enter the Zo (System Impedance) and the branch loss desired. When Calculate is pressed the Rs, Rt and Ru resistance and the Loss for branch 2 will be computed and displayed. Press Clear to clear all values and retry the calculation or Close to close the screen and return to the main menu.

 

Figure 41 – Attenuator Un-Equal Divider

Matching LC Pads

This section helps the user voltage match using resisters, capacitors and/or inductors. The users inputs the V AC input voltage (units relative to output so Vpeak, Vrms, Vavg, etc.). Enter the frequency the voltage divider will work at in Hertz (Hz). Also select the proper radio button for the type of divider component desired (R, L, C) and the respective values. Then press Calculate to compute the upper and lower impedance and the voltage at the output of the divider. Press Clear to clear the boxes and reenter to try again or Close to quit and return to the main menu.

 

Figure 42 - Attenuator LC Matching Pad