**These programs are distributed in the hope that they will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.**

**Most are made available under the terms of the GNU General Public License as published by the Free Software Foundation, either version 2 of the License, or (at your option) any later version, but see the License conditions for each individual program.**

These programs are in the form of Web Widgets which execute within a web browser. They are coded in HTML, CSS and javascript.

In many cases the files may also be downloaded for local use in a web browser. This may require modification of the browser's security settings.

Information about most widgets can be obtained by clicking on the **HELP buttons** or on the **blue help balloons**.

Many of the simple calculators require the user to enter data and then **press the RETURN or ENTER key**.

This is a special purpose calculator which performs simple 3-phase alternating
current calculations.

Given three of the four quantities voltage, current, power factor and power, the Widget
calculates the value of the fourth.

Two formulae are used, one for line voltages and currents, the other for phase voltages
and currents.

Direct Link or download the files for local use in your browser.

Attenuator is a special purpose calculator for the design of passive resistive attenuators
and impedance matching circuits.

The Widget can assist in the design of PI-network, T-network, BT-network, B-network
and L-network attenuators and impedance matching circuits.

It can perform single calculations and (in symmetric cases) generate tables for later use.

Direct Link or download the files for local use in your browser.

This is a special purpose calculator which calculates the properties of a single-layer air-spaced coil. Given three parameters, the Widget calculates the value of a fourth.

Direct Link or download the files for local use in your browser.

Convert Time converts local time to various other time formats.

Direct Link or download the files for local use in your browser.

Convert Unix Time converts Unix time-stamps to various other time formats, including Local Time, Universal Time, NTP Time, Internet Time, Julian Date, and GPS Week. It can also function as a clock in any of its time formats.

Direct Link or download the files for local use in your browser.

DMXconverter is a special purpose calculator Widget for use with DMX512 installations. It converts between full channel numbers and the corresponding DMX channel settings.

Direct Link or download the files for local use in your browser.

HexDeCoder is a simple hexadecimal, decimal, octal and binary number converter Widget.

There is also an option to choose a custom base/radix between 2 and 36 and an option to
convert between Unicode characters and their UTF-16 or UTF-8 character encodings.

Direct Link or download the files for local use in your browser.

This web widget calculates the hyperfocal distance of a lens.

Direct Link or download the files for local use in your browser.

This is a special purpose calculator which computes properties of intersecting circles.

Direct Link or download the files for local use in your browser.

Direct Link or download the files for local use in your browser.

This is a special purpose calculator for the analysis of LCR resonant circuits.

Direct Link or download the files for local use in your browser.

The L-Section Calculator is a special purpose calculator which computes the component values for L-Section impedance matching filters.

Direct Link or download the files for local use in your browser.

This is a special purpose calculator which computes the optical power of a lens using the Lensmaker's Equation.

Direct Link or download the files for local use in your browser.

Lunar Date converts between Gregorian dates and approximate lunar dates. It also displays the Julian date and the day of the week.

Direct Link or download the files for local use in your browser.

NGR Converter is a National Grid Reference to latitude and longitude converter.

The widget converts between British National Grid References, latitude and longitude, IARU Locators and Plus Codes.

Direct Link or download the files for local use in your browser.

NetCalc is broadly based on the program NETCALC by Ian White. NETCALC was described by Ian as a simple impedance calculator for working out Radio Frequency network design ideas.

Direct Link or download the files for local use in your browser.

Direct Link for browser (wide) version

This is an emulation of an abacus.

Direct Link or download the files for local use in your browser.

This is a special purpose calculator which performs simple calculations using Ohm's Law. Given any two of the four quantities - voltage, current, resistance or power - the Widget calculates the values of the other two.

Direct Link or download the files for local use in your browser.

The PIN (De)Coder Widget provides a simple means of encrypting and decrypting four-digit PIN numbers.

Direct Link or download the files for local use in your browser.

The Resistors Calculator is a special purpose calculator which can be used to decode the colored bands on resistors (and some small capacitors).

Direct Link or download the files for local use in your browser.

This is an emulation of a Roman Abacus.

Direct Link or download the files for local use in your browser.

This is a general purpose calculator which also features Roman numbers.

Direct Link or download the files for local use in your browser.

This is a general purpose calculator which also features Roman and hexadecimal numbers.

Direct Link or download the files for local use in your browser.

The Series to Parallel Converter is a special purpose calculator which converts between very simple Series and equivalent Parallel circuits.

Direct Link or download the files for local use in your browser.

Sunrise Calculator computes and displays the times of sunrise and sunset, given a
latitude, a longitude and a date.

The calculator can make allowances for altitudes of up to 15,240 metres (50,000 feet). The
altitude compensation calculation, performed by the calculator, is not part of the published
algorithm, on which the main calculation is based, and should be treated with caution.

This version also computes and displays the times of moonrise and moonset.

Direct Link or download the files for local use in your browser.

This is a special purpose calculator which converts toric lens descriptions between the two standard formats. It can also add the powers of two toric lines.

Direct Link or download the files for local use in your browser.

This is a special purpose calculator which performs simple transmission line calculations. Given three line parameters, the Widget calculates the value of a fourth. Two formulae are used, one for coaxial cable, the other for parallel line.

Direct Link or download the files for local use in your browser.

This is a special purpose calculator which performs simple wiring calculations for copper wires used in low voltage circuits.
Given three of the four quantities circuit length, current, wire cross section and voltage drop, the Widget calculates the value of the
fourth.

WARNING: The calculator was designed to calculate the voltage drop in low voltage (12/24 volt) marine circuits where the voltage drop
due to long wire circuits is more often a problem than the current carrying capacity of the wires.
No attempt has been made to ensure that the results of any of the calculations conform to current electrical codes,
such as the NEC or IEC codes. Users must check these and other safety matters for themselves.

The user can choose to work in SI units or USA units.

Direct Link or download the files for local use in your browser.

Last updated Wednesday, June 17, 2020.