Version 2.4

Content Rating 4+

User Rating 5 / 5

# Ohm's Law Calculator & Guide

## Mr Combi Sales Ltd.

### Productivity, Utilities

IOS
GBP 0.00

This is an Ohm's Law Calculator with a built-in mini-guide to refer to if required.

The calculator is very easy to use, enter two known values, select the units, press 'Calculate' and the other two values will be displayed instantly!

The guide contains 7 parts:

• Ohm's law
• Watt's law
• Voltage formulae
• Current formulae
• Resistance formulae
• Power formulae

If you want to be able to understand how the Ohm's law calculations are carried out, or would like a handy reference guide, this is the app for you!

Release notes

We've made some small tweaks for iOS 12.

### The Developer Mr Combi Sales Ltd. also wrote the apps listed below, click the icon to visit the pages.

Gas Pipe Sizing Calculator

£1.99
A study carried out by Worcester Bosch Group's technical support team found that the most common cause of a boiler installation problem was from incorrectly sized gas pipes. When fitting a new boiler, often the existing pipes should be replace for larger ones due to the increased output. Smaller pipes will mean the boiler is running at a lower power and can cause an increase in carbon monoxide levels.

The Gas Pipe Sizing Calculator is an extremely easy to use app that will help you to select the right size pipes for installations using copper (up to 108mm), steel (up to 300mm) and PE (up to 315mm) pipes of sections up to 250m (820ft) in length.

To carry out a calculation simply select the gas type, enter the appliance heat input, enter the pipe length, the number of high or low loss fittings (guidance is given in the app), select the type of pipe and then press the 'Calculate' button.

The results will show the total equivalent length, the minimum pipe diameter (metric) that should be used and the pressure drop for that section of pipe.

For multiple appliances each section should be calculated in turn and the kW inputs for the appliances in each section added together for each calculation.

The maximum pressure drop from each appliance to the meter should be no more than 1 mbar for natural gas or 2.5 mbar for butane or propane. Adding all drops together using the minimum pipe diameters may cause this to be exceeded. Where possible, the results will also calculate the drop if the next larger size pipe diameter is selected on a section, this should help to ensure the right sizes are used throughout the whole circuit.

Please note: This app is designed mainly for the UK so supports metric pipe sizes only....
Gas Ventilation Calculator UK

£1.99
The Gas Ventilation Calculator will help you find the required ventilation sizes for domestic flueless, open flue and room sealed appliances up to 70kW (net). It also supports multiple rooms, multiple appliances and includes an extractor fan calculator and a vent size calculator.

Flueless:
This calculator will find the required vent size for flueless appliances such as cookers, grills, water heaters and fires. Enter the dimensions of the room and the heat input of the appliance and the calculator will find the vent size required or advise if no vent is needed or that the appliance should not be fitted in that room.

Open Flue:
Enter the appliance heat input and select whether adventitious air is available or if the appliance is in a compartment and the calculator will find the required vent sizes.

Multiple Rooms:
For an open flue appliance where the path to outside is via another room use the 'Walls to outside' option within the Open Flue Calculator to select the number of walls vents need to be fitted into. It will also take into account adventitious air or if the appliance in a compartment as per the selected options.

Room Sealed:
For a room sealed appliance simply enter the heat input and the calculator will find the vent sizes required if the appliance is in a compartment.

Multiple Appliances:
For multiple appliances in one room this app simply provides a guide to remind you of the regulations. The other calculators will then need to be used to find the required vent size.

Extractor Fan:
To find the required performance of a fan for a room enter the room dimensions and type and the performance will be found using pre-set air change rates. A manual ACH can be entered also.

Vent Size:
A calculator is included to find the total size of a vent with rectangular or circular holes....
Gas Rate Calculator Lite

Free
You can now get the hugely popular Gas Rate Calculator & Guide on your iPhone or iPad. This is the free Lite version of the app to which supports metric and imperial meters with natural gas only.

Metric:
Input the initial meter reading, use the built in 2 minute timer and then input the final reading. Press the calculate button and the results will then be displayed.

Imperial:
The app comes with a built in stopwatch and could not be easier to use: start the stopwatch and after a complete rotation of the test dial press stop and the results will be displayed instantly!

Gas rates are given in cubic metres per hour, litres per second and cubic feet per hour. Gross and net heat inputs are given in megajoules per hour, kilowatts and BTUs per hour....
Ohm's Law Calculator & Guide

Free
This is an Ohm's Law Calculator with a built-in mini-guide to refer to if required.

The calculator is very easy to use, enter two known values, select the units, press 'Calculate' and the other two values will be displayed instantly!

The guide contains 7 parts:

• Ohm's law
• Watt's law
• Voltage formulae
• Current formulae
• Resistance formulae
• Power formulae

If you want to be able to understand how the Ohm's law calculations are carried out, or would like a handy reference guide, this is the app for you!...
Wiring & Controls - Diagrams

£3.99
With special permission from Danfoss and Honeywell, we took their wiring diagrams and turned them into fantastic coloured wiring diagrams which are much easier to follow. We've been using these diagrams on our training course for over two years and everyone agrees that they're essential for wiring up controls on two and three port installations.

• Colour diagrams for Danfoss and Honeywell systems
• 2 and 3 port systems
• Fully Wired diagrams - Shows every wire in the control circuit
• Live Wire diagrams - The earth and neutral wire have been removed for clarity
• Schematic diagrams - A simplified version of the circuit
• Stats diagrams - Only the thermostat circuit is shown
• Danfoss and Honeywell wiring centre schematics
• Frost protection diagrams
• Fault finding charts for Danfoss systems...