Project Files of Fuse Library for Proteus: 5x20 Glass Fuse and Resettable PTC

FUSE LIBRARY FOR PROTEUS - V1.0 (a 5x20 glass fuse that blows and a PTC that trips and resets, with a pop-up)
Designed by The Engineering Projects
www.TheEngineeringProjects.com

IMPORTANT LINKS
Article (read it first - pictures, step by step, every feature explained):
  https://www.theengineeringprojects.com/2026/11/fuse-library-for-proteus.html
Report a bug or suggest a feature (our forum):
  https://www.theengineeringprojects.com/forum/category/fuse-proteus-library
The demo runs on our Arduino UNO V4.0 (included) - working LEDs, RESET and a
built-in serial monitor, no Virtual Terminal to wire - its own article:
  https://www.theengineeringprojects.com/2026/10/arduino-uno-library-for-proteus-v40.html
The demo's loads are our own power resistors (included):
  https://www.theengineeringprojects.com/2026/11/power-resistor-library-for-proteus.html
Its short buttons are our own push buttons (included):
  https://www.theengineeringprojects.com/2026/11/push-button-library-for-proteus.html
Support us (the libraries are free):
  https://www.theengineeringprojects.com/donate

FILE STRUCTURE
Fuse-TEP-v1.0/
|-- Proteus Library Files/
|   |-- ArduinoV4TEP.LIB                              201.9 KB   TEP Arduino boards V4.0 (UNO) -> LIBRARY
|   |-- TEPBUTTON.LIB                                  20.7 KB   a part the demo uses -> LIBRARY folder
|   |-- TEPFUSE.LIB                                    13.8 KB   the library -> LIBRARY folder
|   |-- TEPPOWERRES.LIB                               157.2 KB   a part the demo uses -> LIBRARY folder
|-- Proteus Model Files/
|   |-- TEPARDUINO.DLL                                883.5 KB   the Arduino board model -> MODELS folder
|   |-- TEPBUTTON.DLL                                 274.0 KB   its model -> MODELS folder
|   |-- TEPFUSE.DLL                                   303.5 KB   the model -> MODELS folder
|   |-- TEPPOWERRES.DLL                               304.5 KB   its model -> MODELS folder
|-- Proteus Simulation/
|   |-- Fuse_Watch_Demo.hex                            14.2 KB   the demo firmware
|   |-- Fuse-Watch-ArduinoUnoV4.pdsprj                 22.0 KB   the demo project
|   |-- TEPARDUINO.DLL                                883.5 KB   copy of the board model
|   |-- TEPBUTTON.DLL                                 274.0 KB   copy of its model
|   |-- TEPFUSE.DLL                                   303.5 KB   copy of the model
|   |-- TEPPOWERRES.DLL                               304.5 KB   copy of its model
|-- Arduino Code/
|   |-- Fuse_Watch_Demo/Fuse_Watch_Demo.ino             1.5 KB   the demo sketch (source of the .hex)
|-- README.txt                                        ~13.1 KB   this file
Total: 3.88 MB (unzipped). The C++ source code of the models is not included.

WHAT IS IT?
Fuses, drawn at true scale. Two kinds:
  * A 5 x 20 mm glass cartridge fuse with pigtail leads, F1A: the wire you can see melts when the
    current stays too high for too long, on the IEC 60127
    curve (fast F or slow T). It never blows below about 2.1 x its rating. Once blown it stays open:
    fit a new one from the pop-up.
  * A resettable PTC fuse (Bourns MF-R050 style): a yellow disc, hold 0.5 A, trip 1.0 A, 0.4 ohm.
    Past its trip current it heats and turns into a high
    resistance that burns its trip power (0.75 W) to stay hot - for as long as the circuit can feed
    that power. When it cannot, it cools and resets.
  * Both heat with the square of the current: a big short opens them in milliseconds, a small
    overload in seconds.
  * Click one at Run for the pop-up: the current against its rating, the heat on its way to blowing,
    the time-current curve, graphs, an event log and a
    check page.
The body is drawn as on the real part and to true scale against our Arduino.
The TEP signature and the pop-up are TEP additions.

TWO DEVICES (search "FUSE" in Pick Devices):
  FUSEGLASS5X20TEP   "Fuse 5x20 Glass V1.0" in TEPFUSE.LIB (Miscellaneous > Fuses), prefix F, model
  TEPFUSE.DLL. Pins 1 and 2.
  FUSEPTCTEP         "Resettable Fuse PTC V1.0" in TEPFUSE.LIB (Miscellaneous > Fuses), prefix F,
  model TEPFUSE.DLL. Pins 1 and 2.

THE POP-UP
Click the part at Run. Tabs:
    Fuse       the state (OK, OVERLOAD with the time left, BLOWN or TRIPPED), the fuse or the PTC
    drawn large, the time against current curve with the
               present current on it, and eight live values. The toolbar: New part.
    Graphs     the live values over the last 2, 6 or 15 s. Live / Freeze.
    Event log  every change and warning; filters All / Changes / Warnings, Pause, Clear
    Check      what the part is doing and what to look at, each with a verdict (green = fine, amber
    = check, red = wrong)
    Settings   theme, text size, open at Run, window size
    Help       report a bug, suggest a feature, article, updates, donate, forum; Copy diagnostics
    for a bug report

TEST STATUS
V1.0: verified in Proteus 8.5 on 31 Oct 2026 (the demo project as shipped: an A4 sheet, an Arduino UNO V4.0).
What the runs showed (the model's own numbers and the sketch's monitor):
  * The project loads and starts cleanly; both loads are fed: load 1 at 4.96 V (0.50 A through F1,
    the glass F1A fuse), load 2 at 4.81 V (0.48 A
    through F2, the 0.5 A PTC, whose 0.4 ohm drops 0.19 V).
  * A tap on SW1 shorted load 1: 25.1 A melted F1's wire in 4.9 ms (the button's contacts bounce as
    they close). The fuse stayed open (5.00 V across it) and load 1 read 0.00 V - NO POWER.
  * SW2 held down shorted load 2: F2 tripped after 0.22 s at 10.0 A, settling at 33.1 ohm and 0.150
    A, burning its 0.75 W to stay hot.
  * SW2 let go: the 10 ohm load could not feed 0.75 W, so F2 cooled and reset by itself; load 2 came
    back to 4.81 V (one trip, one reset).
  * New part on F1: a new fuse, and load 1 back at 4.96 V.
  * The pop-up: Fuse, Graphs, Event log, Check - all four pages followed the run, for both fuses.

INSTALLATION (about 2 minutes)
1. Close Proteus. Extract the WHOLE ZIP to a normal folder (e.g. Desktop).
2. Copy everything in "Proteus Library Files" (TEPFUSE.LIB, TEPPOWERRES.LIB, TEPBUTTON.LIB and our
Arduino library V4.0, ArduinoV4TEP.LIB, with the ARDUINO UNO V4.0 used by the demo) to the LIBRARY
folder of Proteus, for example:
     C:\Program Files (x86)\Labcenter Electronics\Proteus 8 Professional\LIBRARY
   (use the folder that already holds Proteus's own .LIB files).
3. Copy TEPFUSE.DLL, TEPPOWERRES.DLL, TEPBUTTON.DLL and TEPARDUINO.DLL from "Proteus Model Files" to
the MODELS folder (...\Proteus 8 Professional\MODELS).
4. Delete TEPFUSE.IDX from the LIBRARY folder if it is there (Proteus makes a new index).
5. Start Proteus. In Pick Devices (P) search "FUSE".

RUN THE DEMO
"Proteus Simulation\Fuse-Watch-ArduinoUnoV4.pdsprj" (an A4 sheet) - keep the .hex file and the DLLs
beside the project.
  ARD1:   Arduino UNO V4.0 running Fuse_Watch_Demo.hex, its serial monitor built in (window "TEP
  Arduino UNO - ARD1").
  F1, R1, SW1: +5V - the glass F1A fuse - LOAD1 (A0) - a 10 ohm, 5 W load - GND; SW1 (our push
  button) shorts LOAD1 to GND.
  F2, R2, SW2: +5V - the 0.5 A PTC - LOAD2 (A1) - a 10 ohm, 5 W load - GND; SW2 shorts LOAD2 to GND.
  1. Press Run. Both loads are fed; the monitor prints their voltage and current.
  2. Click SW1, or open its pop-up and click Press: the glass fuse blows. Fit a new one with New
  part on F1's pop-up.
  3. Hold SW2 down: the PTC trips. Let go: it resets by itself a moment later.
Closed the monitor? Click the UNO's USB port.

WIRING (the same in Proteus and on a real board)
  supply - the fuse - the load : the fuse first, as close to the supply as you can
  a PTC on a USB port or a battery pack : it resets itself after a fault
REAL HARDWARE:
 * A fuse protects the wiring and the supply, not the load. Size it at about 1.5 x the normal
   current, and for the wire it feeds.
 * Use a slow (T) fuse for loads that start with a surge: motors, lamps, big capacitors.
 * After a fuse blows, find the fault before you fit a new one - and never a bigger one.
 * A PTC is slower than a fuse and does not open fully; it suits low voltages and faults that clear
   themselves.

THE DEMO SKETCH ON THE SERIAL MONITOR (Fuse_Watch_Demo V1.0, 9600 baud)
There are no commands. The sketch prints the voltage and the current of each load when either
changes, at most twice a second.
EXPECTED MONITOR OUTPUT
  Fuse watch - The Engineering Projects
  Load 1: 4.96 V, 0.50 A - powered  |  Load 2: 4.81 V, 0.48 A - powered
  Load 1: 0.00 V, 0.00 A - NO POWER  |  Load 2: 4.81 V, 0.48 A - powered

PROPERTIES (double-click the part > Edit Properties)
  Rating, A (VALUE)                1A for the glass fuse; 0.5A, the hold current, for the PTC
  Characteristic (glass)           F (fast) or T (slow)
  Cold resistance, ohm             0.1 (glass) or 0.4 (PTC)
  Trip current, A (PTC)            1.0
  Power while tripped, W (PTC)     0.75
Every run starts again from the properties.

LINKS.INI (OPTIONAL)
The Help page cards of the pop-up open web pages. To point them somewhere else without a new DLL,
put a text file named links.ini next to TEPFUSE.DLL with lines KEY=URL, for example:
  ARTICLE=https://www.theengineeringprojects.com/...
Keys: WEBSITE, FORUM, BUG_REPORT, FEATURE_REQUEST, ARTICLE, USER_GUIDE,
UPDATE_CHECK, DONATE. Only http:// and https:// links are used; lines starting
with # are comments.

TROUBLESHOOTING
* The fuse blows at once on Run: the load takes more than about 2 x its rating. Check the load, or
  use a bigger (or slow) fuse.
* It never blows: the current never passes about 2.1 x its rating, or the short is not a short
  (check the button's wiring).
* The PTC never resets: the circuit can still feed its trip power. Remove the fault, or the power.
* The pop-up shows OVERLOAD with a time: that is how long it will last at this current.
* The part is not simulated: TEPFUSE.DLL is missing from MODELS and from the project folder. No UNO
  / no monitor window: TEPARDUINO.DLL is missing, or click the UNO's USB port.

BUG REPORTS AND FEATURE REQUESTS
Please post them in our forum with a screenshot, the Serial Monitor text, the
simulation log and the pop-up's Copy diagnostics text:
  https://www.theengineeringprojects.com/forum/category/fuse-proteus-library

SUPPORT US
This library is free. If it saves you time, please support our work:
  https://www.theengineeringprojects.com/donate

WEBSITE
  https://www.theengineeringprojects.com/

LICENCES AND THIRD-PARTY NOTES
* The model (TEPFUSE.DLL), the symbols and artwork, the other parts of ours in the demo and the
  Arduino Library V4.0 (ArduinoV4TEP.LIB / TEPARDUINO.DLL, with its built-in TEP Serial Monitor
  Advance) are made by The Engineering Projects. The models use only standard Windows libraries; no
  Visual C++ redistributable is needed.
  The C++ source code is not included.
* Arduino UNO V4.0 (ArduinoV4TEP.LIB / TEPARDUINO.DLL, our Arduino Library V4.0 - its
  microcontroller is Proteus's own AVR model): The Engineering Projects,
  https://www.theengineeringprojects.com/2026/10/arduino-uno-library-for-proteus-v40.html
* The .hex file is built from the demo sketch and the Arduino AVR core 1.8.6, which includes
  LGPL-licensed code; its source code is available at
  https://github.com/arduino/ArduinoCore-avr/tree/1.8.6
* Proteus is a product of Labcenter Electronics and is not included. Arduino is a trademark of Arduino SA.
  This library is not made or endorsed by Arduino or Labcenter.

REBUILDING THE FIRMWARE (OPTIONAL)
The HEX file is supplied; Arduino IDE is not needed to run the demo. To edit the sketch, open
Arduino Code\Fuse_Watch_Demo\Fuse_Watch_Demo.ino, select Arduino Uno and use Sketch > Export
Compiled Binary. Replace the simulation's .hex with the exported HEX. The sketch needs 5,162 bytes
of flash and 225 bytes of RAM.

MODEL SCOPE AND LIMITS
Modelled: the cold resistance, the heat with the square of the current and its time constant (the
IEC 60127 shape), the melting, the PTC's trip,
its self-held high resistance and its reset.
Not modelled: the arc as the wire parts, the voltage and breaking ratings, the ambient temperature's
effect on the rating.

VERSION
TEP Fuse library V1.0 (Nov 2026). Devices FUSEGLASS5X20TEP and FUSEPTCTEP (TEPFUSE.LIB /
TEPFUSE.DLL). Demo sketch Fuse_Watch_Demo V1.0. Demo board: ARDUINO UNO V4.0 (TEP Arduino Library
V4.0) with its built-in serial monitor.