Project Files of Small Transistors Library for Proteus: 2N2222A, BC547, 2N2907A, BC557

SMALL TRANSISTORS LIBRARY FOR PROTEUS - V1.0 (2N2222A, BC547B, 2N2907A and BC557B in TO-92 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/small-transistors-library-for-proteus.html
Report a bug or suggest a feature (our forum):
  https://www.theengineeringprojects.com/forum/category/small-transistors-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 other parts are all our own (included) - the resistors:
  https://www.theengineeringprojects.com/2026/11/resistor-library-for-proteus.html
the potentiometer:
  https://www.theengineeringprojects.com/2026/11/potentiometer-library-for-proteus.html
the mini speaker:
  https://www.theengineeringprojects.com/2026/11/mini-speaker-library-for-proteus.html
Support us (the libraries are free):
  https://www.theengineeringprojects.com/donate

FILE STRUCTURE
Small-Transistors-TEP-v1.0/
|-- Proteus Library Files/
|   |-- ArduinoV4TEP.LIB                              201.9 KB   TEP Arduino boards V4.0 (UNO) -> LIBRARY
|   |-- TEPBJT.LIB                                     18.6 KB   the library -> LIBRARY folder
|   |-- TEPELECTRO.LIB                                 10.1 KB   a part the demo uses -> LIBRARY folder
|   |-- TEPLED5MM.LIB                                  21.8 KB   a part the demo uses -> LIBRARY folder
|   |-- TEPPOT.LIB                                    208.6 KB   a part the demo uses -> LIBRARY folder
|   |-- TEPRESISTOR.LIB                               306.9 KB   a part the demo uses -> LIBRARY folder
|   |-- TEPSPEAKER.LIB                                 11.0 KB   a part the demo uses -> LIBRARY folder
|-- Proteus Model Files/
|   |-- TEPARDUINO.DLL                                883.5 KB   the Arduino board model -> MODELS folder
|   |-- TEPBJT.DLL                                    292.0 KB   the model -> MODELS folder
|   |-- TEPELECTRO.DLL                                294.5 KB   its model -> MODELS folder
|   |-- TEPLED5MM.DLL                                 289.5 KB   its model -> MODELS folder
|   |-- TEPPOT.DLL                                    310.0 KB   its model -> MODELS folder
|   |-- TEPRESISTOR.DLL                               311.0 KB   its model -> MODELS folder
|   |-- TEPSPEAKER.DLL                                286.0 KB   its model -> MODELS folder
|-- Proteus Simulation/
|   |-- Small-Transistors-ArduinoUnoV4.pdsprj          30.7 KB   the demo project
|   |-- TEPARDUINO.DLL                                883.5 KB   copy of the board model
|   |-- TEPBJT.DLL                                    292.0 KB   copy of the model
|   |-- TEPELECTRO.DLL                                294.5 KB   copy of its model
|   |-- TEPLED5MM.DLL                                 289.5 KB   copy of its model
|   |-- TEPPOT.DLL                                    310.0 KB   copy of its model
|   |-- TEPRESISTOR.DLL                               311.0 KB   copy of its model
|   |-- TEPSPEAKER.DLL                                286.0 KB   copy of its model
|   |-- Transistor_Demo.hex                            18.1 KB   the demo firmware
|-- Arduino Code/
|   |-- Transistor_Demo/Transistor_Demo.ino             2.1 KB   the demo sketch (source of the .hex)
|-- README.txt                                        ~13.8 KB   this file
Total: 6.03 MB (unzipped). The C++ source code of the models is not included.

WHAT IS IT?
Four of the most used small transistors, drawn at true scale in TO-92 (4.6 x 4.6 mm, the flat face
towards you, legs on 2.54 mm):
  * 2N2222A - NPN, E B C, 40 V, 600 mA, 625 mW, hFE 100 to 300: the classic switching transistor.
  * BC547B  - NPN, C B E, 45 V, 100 mA, 500 mW, hFE 200 to 450: the classic small-signal transistor.
  * 2N2907A - PNP, E B C, 60 V, 600 mA, 625 mW: the 2N2222A's complement.
  * BC557B  - PNP, C B E, 45 V, 100 mA, 500 mW: the BC547B's complement.
  * One analog model: a Gummel-Poon-style transistor - the two junctions, the Early effect (the
    slope of the curves), high injection (beta falls
    at high current) - solved with SPICE's junction limiting, so it converges like a SPICE
    transistor.
  * It names its region (cut off, active, saturated, reverse), draws its output curves with the
    working point on them, and heats with its power;
    held past twice its rating it fails short C to E, as real ones do, until New part.
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.

FOUR DEVICES (search "2N2222", "2N2907", "BC547" or "BC557" in Pick Devices):
  Q2N2222ATEP   "2N2222A NPN V1.0" in TEPBJT.LIB (Transistors > Bipolar), prefix Q, model
  TEPBJT.DLL. Pins 1 E, 2 B, 3 C.
  BC547BTEP     "BC547B NPN V1.0" in TEPBJT.LIB, prefix Q, model TEPBJT.DLL. Pins 1 C, 2 B, 3 E.
  Q2N2907ATEP   "2N2907A PNP V1.0" in TEPBJT.LIB, prefix Q, model TEPBJT.DLL. Pins 1 E, 2 B, 3 C.
  BC557BTEP     "BC557B PNP V1.0" in TEPBJT.LIB, prefix Q, model TEPBJT.DLL. Pins 1 C, 2 B, 3 E.

THE POP-UP
Click the part at Run. Tabs:
    Transistor the region and what it means, the TO-92 drawn with its live pins, the output curves
    (Ic against Vce at four base currents) with the
               working point on them, and eight live values. The toolbar: New part, and the pinout.
    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. (Before the runs, the model's stamp was checked against a
    separate Newton solution of a switch, an amplifier,
    a PNP high-side switch and an emitter follower.)
  * Q1, BC547B, with RV1 at 30 %: active - Ib 16.9 uA, Ic 4.92 mA, beta 291 (the BC547B's hFE is 200
    to 450), Vce 2.20 V; the red LED half lit.
    RV1 to 100 %: saturated - Ib 91 uA, Ic 13.7 mA, Vce 0.10 V, Ic / Ib 150 (only just saturated:
    the Check page says so). RV1 to 0 %: cut off.
    Swept: the log named every region - cut off, active, saturated - and the monitor printed the
    collector from 3.97 V down to 0.12 V.
  * Q2, BC557B PNP high-side switch: D4 LOW saturated it - Ib 0.43 mA, Ic 13.2 mA, Vce -0.04 V - and
    lit the green LED every other second.
  * Q3 2N2222A + Q4 2N2907A push-pull into the speaker through 100 uF: paused in a note, Q4 was
    taking over (4.1 mA and rising, beta 247) while Q3 sat cut off,
    its base 0.69 V below its emitter; in the other half cycle they swap. About 72 mW each on
    average; in an earlier run Q3 pushed 136 mA (beta 138).
  * The pop-up: Transistor, Graphs, Event log, Check - all four pages followed the run, for every
    transistor.

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" (TEPBJT.LIB, TEPRESISTOR.LIB, TEPPOT.LIB,
TEPLED5MM.LIB, TEPELECTRO.LIB, TEPSPEAKER.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 TEPBJT.DLL, TEPRESISTOR.DLL, TEPPOT.DLL, TEPLED5MM.DLL, TEPELECTRO.DLL, TEPSPEAKER.DLL and
TEPARDUINO.DLL from "Proteus Model Files" to the MODELS folder (...\Proteus 8 Professional\MODELS).
4. Delete TEPBJT.IDX from the LIBRARY folder if it is there (Proteus makes a new index).
5. Start Proteus. In Pick Devices (P) search "2N2222, 2N2907, BC547 or BC557".

RUN THE DEMO
"Proteus Simulation\Small-Transistors-ArduinoUnoV4.pdsprj" (an A4 sheet) - keep the .hex file and
the DLLs beside the project.
  ARD1:   Arduino UNO V4.0 running Transistor_Demo.hex, its serial monitor built in (window "TEP
  Arduino UNO - ARD1").
  Q1 BC547B: RV1 (our pot) - R1 47k - base; +5V - R2 220 - D1 (red LED) - collector (also to A0);
  emitter to GND.   An LED dimmer.
  Q2 BC557B: emitter +5V; base - R3 10k - D4; collector - R4 220 - D2 (green LED) - GND.   A
  high-side switch.
  Q3 2N2222A + Q4 2N2907A: collectors +5V and GND; bases together - R5 220 - D9; emitters together -
  C1 100 uF - LS1 (our speaker) - GND.   A push-pull.
  1. Press Run. The green LED blinks; every 4 s an arpeggio plays; the monitor prints Q1's
  collector.
  2. Turn RV1 (its pop-up's chips, or Sweep): Q1 goes from cut off through active to saturated, and
  the red LED with it.
Closed the monitor? Click the UNO's USB port.

WIRING (the same in Proteus and on a real board)
  NPN low-side switch:  load from +V to C, E to GND, pin - R - B   (R = (Vpin - 0.7) / (Ic / 10))
  PNP high-side switch: E to +V, load from C to GND, pin - R - B; pin LOW = on (only when +V is the
  pin's own supply)
REAL HARDWARE:
 * Check the pinout: 2N2222A / 2N2907A are E B C; BC547 / BC557 are C B E - the same body, opposite
   ends.
 * Never drive a base straight from a pin: always a resistor.
 * For a switch, give it Ib = Ic / 10 or more, so it saturates hard and stays cool.
 * A push-pull output has a dead band of about 0.6 V each way (crossover); fine for tones, not for
   hi-fi.

THE DEMO SKETCH ON THE SERIAL MONITOR (Transistor_Demo V1.0, 9600 baud)
There are no commands. The sketch blinks Q2's LED, plays an arpeggio through Q3 and Q4 every 4 s,
and prints Q1's collector once a second.
EXPECTED MONITOR OUTPUT
  Transistors - The Engineering Projects
  Turn RV1 to dim the red LED through Q1
  Q1 collector: 2.20 V  |  green LED on

PROPERTIES (double-click the part > Edit Properties)
  Part (VALUE)                     the part's name, as printed on it (2N2222A, BC547B, 2N2907A,
  BC557B)
  The model's parameters are the part's own; there is nothing to set.
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 TEPBJT.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
* REVERSE ACTIVE on the pop-up: C and E are swapped - check the part's pinout.
* It never turns off: the base still gets current (a PNP's base must go all the way to its emitter's
  voltage).
* Only just saturated (amber): give it more base current - a smaller base resistor.
* FAILED: it ran past twice its power rating; find why, then New part.
* The part is not simulated: TEPBJT.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/small-transistors-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 (TEPBJT.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\Transistor_Demo\Transistor_Demo.ino, select Arduino Uno and use Sketch > Export
Compiled Binary. Replace the simulation's .hex with the exported HEX. The sketch needs 6,582 bytes
of flash and 248 bytes of RAM.

MODEL SCOPE AND LIMITS
Modelled: both junctions, the Early effect, high injection, the regions, the power, the heating and
the short-circuit failure.
Not modelled: the junction capacitances and switching times, temperature drift of Vbe and beta,
breakdown.

VERSION
TEP Small Transistors library V1.0 (Nov 2026). Devices Q2N2222ATEP, BC547BTEP, Q2N2907ATEP,
BC557BTEP (TEPBJT.LIB / TEPBJT.DLL). Demo sketch Transistor_Demo V1.0. Demo board: ARDUINO UNO V4.0
(TEP Arduino Library V4.0) with its built-in serial monitor.