In the first four parts in this series, we learned about the Voltage Drop, Wire Size, Battery Size, and Standby Time calculators in LifeSafety Power's Excel-based FlexCalculator Suite . If you missed them, those posts can be found here:

In the final part of this series, we will cover the Ohm's Law and Miscellaneous calculations. These calculators perform a variety of calculations such as Power, Resistance, BTU, Weight Conversion, Temperature Conversion, and more. The FlexCalculator Suite can be found on the the Calculators page of our website.

Once the suite is downloaded, open the file. A main menu will appear with buttons for each of the calculator pages. For these exercise, we will use the "Ohm's Law" and "Misc Calcs" buttons. Click the "Main Menu" button from any of the calculators to return.

**Ohm's Law Calculator
**These calculators help you perform Ohm's Law calculations by entering two parameters. Start by clicking the "Ohm's Law" button from the main menu. The Ohm's Law calculator page will appear. There are four independent calculators on this page for Current, Resistance, Voltage, and Power calculations. To perform any of these calculations, enter any two parameters into the blue cells. If all three parameters are entered the calculator will show an error in the result field. Below are two example calculations using the Power calculator - the other calculators operate similarly.

**Example 1 - Using Voltage and Current
**In this example, we will calculate the power drawn by a 24V maglock which draws 273mA and is connected to an FPO75 power supply set for a 24V output.

**Voltage - **In this field, we will enter 25 volts, which is the nominal output voltage setting of an FPO power supply set for a 24V output.

**Current - **In this field we will enter 0.273 Amps for the 273mA current draw of the lock.

**Resistance - **This field will be left blank in this application.

**Power - **This is the result field and cannot be changed directly. In our example, the lock will use 6.825W of the 75W available from the FPO75.

**Example 2 - Using Voltage and Resistance
**In this example, we will calculate the power drawn by a 33 ohm resistor connected to 16V power supply.

**Voltage - **In this field, we will enter 16 volts.

**Current - **In this example, we will leave the current field blank.

**Resistance - **In this field, we will enter 33 ohms.

**Power - **This example results in a total power draw of 7.76 watts.

**Miscellaneous Calculators
**These calculators help you perform various calculations such as BTU, Efficiency, Power Factor, Temperature Conversion, Weight Conversion, Length Conversion, and Series and Parallel Resistors. Start by clicking the "Misc Calcs" button from the main menu. The Miscellaneous Calculations page will appear. There are eight independent calculators on this page. Descriptions of each calculator and their related fields are below.

**Power Supply BTU
**This calculator will give you the total BTU generated by a power supply. The fields are as follows:

**Pin** - This is the power, in watts, drawn by the power supply from the main power source. For this example, our power supply is drawing 170 watts from the AC line.

**Pout** - This is the output power being drawn from the power supply. In our example, this power supply is supplying 150 watts.

**BTU** - This field gives the BTU generated by the power supply. It is a calculated field and cannot be changed directly. In our example, the power supply is generating 68 BTU.

**Efficiency
**This calculator will give you the efficiency of a power supply. The fields are as follows:

**Pin** - This is the power, in watts, drawn by the power supply from the main power source. For this example, our power supply is drawing 170 watts from the AC line.

**Pout** - This is the output power being drawn from the power supply. In our example, this power supply is supplying 150 watts.

**Efficiency** - This field gives the efficiency of the power supply. It is a calculated field and cannot be changed directly. In our example, the efficiency is 88%.

**Power Factor
**This calculator will give you the power factor of a circuit. The fields are as follows:

**Pmeas** - This is the measured power, in watts, of the circuit. For this example, we will use 119.4 watts.

**Vmeas** - This is the measured voltage, in volts, of the circuit. In our example, we will use 120 volts.

**Imeas** - This is the measured current, in amps, of the circuit. In our example, we will use 1.41 amps.

**PF** - This is the Power Factor of the circuit. It is a calculated field and cannot be changed directly. In our example, the PF is 0.71.

**Temp Conversion
**This calculator will convert temperatures between Fahrenheit and Celsius. The fields are as follows:

**Fahrenheit to Celsius
Deg F** - This is the temperature, in degrees Fahrenheit, to be converted. In our example, enter 212 degrees.

**Celsius to Fahrenheit
Deg C** - This is the temperature, in degrees Celsius, to be converted. In our example, enter 100 degrees.

**Weight Conversion
**This calculator will convert weights between Pounds and Kilograms. The fields are as follows:

**Pounds to Kilograms
Lbs**. - This is the weight, in pounds, to be converted. In our example, enter 150 pounds.

**Kilograms to Pounds
kg** - This is the weight, in kilograms, to be converted. In our example, enter 150 kilograms.

**Length Conversion
**This calculator will convert lengths between Inches and Centimeters. The fields are as follows:

**Inches to Centimeters
Inches** - This is the length, in inches, to be converted. In our example, enter 36 inches.

**Centimeters to Inches
cm** - This is the length, in centimeters, to be converted. In our example, enter 100 centimeters.

**Resistors in Series
**This calculator will give you the total resistance of up to four resistors connected in series. The fields are as follows:

**R1** - Enter the first resistor value, in ohms, in this field. For this example, enter 100 ohms.

**R2** - Enter the second resistor value, in ohms. In our example, we will use 89 ohms.

**R3** - Enter the third resistor value, in ohms. Leave this field blank if there are less than three resistors being calculated. In our example, we will use 1000 ohms.

**R4** - Enter the fourth resistor value, in ohms. Leave this field blank if there are less than four resistors being calculated. In our example, we will enter 500 ohms.

**R Total** - This is the total resistance of the series circuit. It is a calculated field and cannot be changed directly. In our example, the total resistance is 1689 ohms.

Note that if more than four resistors need to be calculated, you may calculate the first four resistors, then take that result and enter it in the R1 field. Up to three more resistors may then be entered into the R2, R3, and R4 fields. This process may be repeated an unlimited number of times.

**Resistors in Parallel
**This calculator will give you the total resistance of up to four resistors connected in parallel. The fields are as follows:

**R1** - Enter the first resistor value, in ohms, in this field. For this example, enter 1500 ohms.

**R2** - Enter the second resistor value, in ohms. In our example, we will use 330 ohms.

**R3** - Enter the third resistor value, in ohms. Leave this field blank if there are less than three resistors being calculated. In our example, we will use 750 ohms.

**R4** - Enter the fourth resistor value, in ohms. Leave this field blank if there are less than four resistors being calculated. In our example, we will enter 3000 ohms.

**R Total** - This is the total resistance of the parallel circuit. It is a calculated field and cannot be changed directly. In our example, the total resistance is 186 ohms.

Note that if more than four resistors need to be calculated, you may calculate the first four resistors, then take that result and enter it in the R1 field. Up to three more resistors may then be entered into the R2, R3, and R4 fields. This process may be repeated an unlimited number of times.

We hope that this series has helped you better understand the FlexCalculator Suite and that you will find the calculators helpful in your daily system planning. As always, if you need assistance our Technical Support department is always here to help.