Project Files of Crystal Library for Proteus: 32.768 kHz and HC-49

CRYSTAL LIBRARY FOR PROTEUS - V1.0 (a watch crystal and an HC-49/US crystal that really oscillate, and 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/crystal-library-for-proteus.html
Report a bug or suggest a feature (our forum):
  https://www.theengineeringprojects.com/forum/category/crystal-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
Its amplifier, buffer and switch are our own 2N7000 MOSFETs (included):
  https://www.theengineeringprojects.com/2026/11/n-mosfet-library-for-proteus.html
and its capacitors our own ceramic capacitors (included):
  https://www.theengineeringprojects.com/2026/11/ceramic-capacitor-library-for-proteus.html
Support us (the libraries are free):
  https://www.theengineeringprojects.com/donate

FILE STRUCTURE
Crystal-TEP-v1.0/
|-- Proteus Library Files/
|   |-- ArduinoV4TEP.LIB                              201.9 KB   TEP Arduino boards V4.0 (UNO) -> LIBRARY
|   |-- TEPCERAMIC.LIB                                 36.0 KB   a part the demo uses -> LIBRARY folder
|   |-- TEPCRYSTAL.LIB                                 15.7 KB   the library -> LIBRARY folder
|   |-- TEPNMOS.LIB                                    17.9 KB   a part the demo uses -> LIBRARY folder
|   |-- TEPRESISTOR.LIB                               306.9 KB   a part the demo uses -> LIBRARY folder
|-- Proteus Model Files/
|   |-- TEPARDUINO.DLL                                883.5 KB   the Arduino board model -> MODELS folder
|   |-- TEPCERAMIC.DLL                                300.5 KB   its model -> MODELS folder
|   |-- TEPCRYSTAL.DLL                                328.5 KB   the model -> MODELS folder
|   |-- TEPNMOS.DLL                                   295.0 KB   its model -> MODELS folder
|   |-- TEPRESISTOR.DLL                               311.0 KB   its model -> MODELS folder
|-- Proteus Simulation/
|   |-- Crystal_Demo.hex                               14.8 KB   the demo firmware
|   |-- Crystal-Pierce-ArduinoUnoV4.pdsprj             24.8 KB   the demo project
|   |-- TEPARDUINO.DLL                                883.5 KB   copy of the board model
|   |-- TEPCERAMIC.DLL                                300.5 KB   copy of its model
|   |-- TEPCRYSTAL.DLL                                328.5 KB   copy of the model
|   |-- TEPNMOS.DLL                                   295.0 KB   copy of its model
|   |-- TEPRESISTOR.DLL                               311.0 KB   copy of its model
|-- Arduino Code/
|   |-- Crystal_Demo/Crystal_Demo.ino                   3.3 KB   the demo sketch (source of the .hex)
|-- README.txt                                        ~15.2 KB   this file
Total: 4.76 MB (unzipped). The C++ source code of the models is not included.

WHAT IS IT?
Two quartz crystals, drawn at true scale:
  * A cylindrical 32.768 kHz tuning-fork watch crystal, 2.1 x 6.2 mm, its leads 0.7 mm apart splayed
    to 2.54 mm - as the ECS-.327-12.5-13X:
    cut for 12.5 pF, +-20 ppm, R1 35 kohm max (23.1 kohm from its Q of 70,000), C1 3.0 fF, C0 1.35
    pF, 1 uW drive max, -0.034 ppm/C^2.
  * An HC-49/US low-profile crystal, 11.35 x 4.65 mm, legs 4.88 mm apart, its frequency printed on
    the can (it follows the value you type) - as
    the ECS-80-18-4X: 8 MHz, cut for 18 pF, +-30 ppm, ESR 80 ohm max, C0 7 pF max, 500 uW max. No
    HC-49 datasheet publishes C1: the model's
    15 fF, 40 ohm and 4.5 pF are typical values, not datasheet ones.
  * One analog model: the Butterworth-Van Dyke circuit (R1, L1, C1 in series, C0 across), the
    motional arm integrated EXACTLY over each step
    (the matrix exponential), so a Q of 70,000 keeps its frequency to a small fraction of a ppm. It
    measures what an engineer checks: the
    frequency and its error in ppm (and seconds a day), the load capacitance the circuit gives it,
    the drive level, the start-up time and the
    circuit's negative resistance (the start margin). Proteus starts from a DC point where nothing
    disturbs a crystal, so the model starts it
    with a small current, as switching on does. With no amplifier round it, it rings down and lets
    the simulator take long steps again.
  * Click it at Run for the pop-up: the crystal and its electrical twin with their values, its
    reactance round resonance with where it runs,
    the start-up curve, eight live values, 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 "CRYSTAL" in Pick Devices):
  CRYSTAL32KTEP   "Watch Crystal V1.0" in TEPCRYSTAL.LIB (Crystals > Watch (tuning fork)), prefix X,
  model TEPCRYSTAL.DLL. Pins 1, 2.
  CRYSTALHC49TEP  "HC-49 Crystal V1.0" in TEPCRYSTAL.LIB (Crystals > HC-49), prefix X, model
  TEPCRYSTAL.DLL. Pins 1, 2.

THE POP-UP
Click the part at Run. Tabs:
    Crystal    the crystal and its electrical twin (R1, L1, C1, C0, Q, the series and parallel
    resonances), its reactance from below the series
               resonance to past the parallel one with the line of the CL it is cut for and where it
               runs now, the amplitude since the start
               with its 90 % point, and eight live values: frequency, error (ppm, s a day), the load
               it sees, drive level, motional current,
               start-up time, start margin, temperature.
    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; X1 starts in its 2N7000 Pierce oscillator and reaches 90 %
    of its amplitude at 888 ms. From 1.1 s
    D8's input capture times it every quarter of a second: +6.0, +4.5, +2.3 and +4.0 ppm (an edge
    reaches the UNO on a simulator step,
    about 1 us apart: 4 ppm in a quarter of a second).
  * X1 alone (1.9 s): 32,768.13 Hz, +4.05 ppm (0.35 s a day), the load it sees 12.0 pF (cut for
    12.5), drive 383 nW of its 1 uW, 4.07 uA
    rms in its motional arm, start margin 242 kohm = 6.9 x its 35 kohm worst-case ESR.
  * At 2 s Q3 adds C2 (33 pF) to the drain: OFF FREQUENCY - 32,765.92 Hz, -63.41 ppm (5.48 s a day
    slow), the load 32.1 pF, drive 463 nW;
    the UNO reads -64.2, -62.5 and -63.2 ppm.
  * The pop-up: Crystal (the twin, the reactance curve, the start), Graphs, Event log, Check - all
    four pages followed the run.

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" (TEPCRYSTAL.LIB, TEPNMOS.LIB, TEPCERAMIC.LIB,
TEPRESISTOR.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 TEPCRYSTAL.DLL, TEPNMOS.DLL, TEPCERAMIC.DLL, TEPRESISTOR.DLL and TEPARDUINO.DLL from
"Proteus Model Files" to the MODELS folder (...\Proteus 8 Professional\MODELS).
4. Delete TEPCRYSTAL.IDX from the LIBRARY folder if it is there (Proteus makes a new index).
5. Start Proteus. In Pick Devices (P) search "CRYSTAL".

RUN THE DEMO
"Proteus Simulation\Crystal-Pierce-ArduinoUnoV4.pdsprj" (an A4 sheet) - keep the .hex file and the
DLLs beside the project.
  ARD1:   Arduino UNO V4.0 running Crystal_Demo.hex, its serial monitor built in (window "TEP
  Arduino UNO - ARD1").
  Oscillator: X1 watch crystal from DRN to GATE; Q1 2N7000 (G GATE, D DRN, S GND); R1 2.2M VCC -
  DRN; R2 10M DRN - GATE; C1 15p on DRN
  Buffer:     Q2 2N7000 (G GATE, D D8); R3 2.2M VCC - D8 (as R1: Q2 copies Q1's working point); C3
  10p on D8
  Load step:  C2 33p from DRN to SW3; Q3 2N7000 (D SW3, S GND, G G3 - R4 100 - D4)
  1. Press Run. X1 starts in a little under a second; D8 (Timer1's input capture) times 8,192 cycles
  to one clock of the UNO and the sketch
     prints the frequency, the error in ppm and the seconds a day.
  2. At 2 s Q3 adds C2 to the drain: the load capacitance grows and the crystal runs slow.
Closed the monitor? Click the UNO's USB port.

WIRING (the same in Proteus and on a real board)
  Pierce oscillator: an inverting amplifier (here a 2N7000 biased by 10M from drain to gate), the
  crystal from its output to its input, a
  capacitor from each side to GND (the transistor's own gate capacitance is one of them here); CL =
  C1 C2 / (C1 + C2) + strays.
REAL HARDWARE:
 * Give the crystal the load capacitance it is cut for, counting the strays and the amplifier's own
   capacitance.
 * Keep the drive level under its limit - a watch crystal's is 1 uW; too much ages it, shifts it and
   can break a tuning fork.
 * The start margin: the circuit's negative resistance should be at least five times the crystal's
   worst-case ESR.
 * Keep the oscillator's tracks short and away from noisy lines; a guard ring round them helps.
 * A real UNO's own clock is a ceramic resonator (+-0.5 %): it cannot measure ppm. In Proteus its
   clock is exact.

THE DEMO SKETCH ON THE SERIAL MONITOR (Crystal_Demo V1.0, 9600 baud)
There are no commands. The sketch times 8,192 cycles of X1 on D8, prints each result and adds C2 at
2 s.
EXPECTED MONITOR OUTPUT
  Watch crystal, 32768 Hz - The Engineering Projects
  t=0.88 s: settling
  t=1.13 s: 32768.19 Hz, 6.0 ppm, 0.52 s a day fast
  t=2.00 s: Q3 adds 33 pF to the drain
  t=2.39 s: 32765.90 Hz, -64.2 ppm, 5.55 s a day slow

PROPERTIES (double-click the part > Edit Properties)
  Frequency (VALUE)                32.768k, 4M, 8M, 12M (k = kHz, M = MHz)
  Load capacitance (CL)            the CL it is cut for, pF
  Motional resistance (ESR)        R1, ohm, or AUTO (the datasheet's typical)
  Motional capacitance (CM)        C1, fF, or AUTO
  Shunt capacitance (C0)           pF, or AUTO
  This part's own error (PPM)      its offset at 25 C, ppm (0: exact)
  Its temperature (TEMP)           C: the watch crystal follows its parabola, the HC-49 a typical AT
  cut's cubic
  Drive level limit (DLMAX)        uW, or AUTO (1 uW, 500 uW)
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 TEPCRYSTAL.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
* IDLE: no oscillation - a crystal needs an amplifier and its load capacitors round it. Proteus's
  microcontroller models take their clock
  from a property, so a crystal on their XTAL pins only rings down.
* It never starts: too little gain (the start margin) or too much load capacitance.
* OFF FREQUENCY: the circuit's load capacitance differs from the CL it is cut for - change the
  capacitors.
* OVERDRIVEN: past its drive limit - a series resistor at the amplifier's output, or less gain.
* "Timestep too small" on a buffer's output: give the node a little capacitance (C3 here).
* The part is not simulated: TEPCRYSTAL.DLL is missing from MODELS and from the project folder.
* The part is not simulated: TEPCRYSTAL.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/crystal-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 (TEPCRYSTAL.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\Crystal_Demo\Crystal_Demo.ino, select Arduino Uno and use Sketch > Export Compiled
Binary. Replace the simulation's .hex with the exported HEX. The sketch needs 5,390 bytes of flash
and 227 bytes of RAM.

MODEL SCOPE AND LIMITS
Modelled: the Butterworth-Van Dyke circuit, the pulling by the load capacitance, the temperature
curves, its own error, the drive level and
the start (from a small current at switch-on).
Not modelled: overtones and spurious modes, aging, the drive level's own effect on the frequency,
damage when overdriven. A high-frequency
crystal needs very small steps (about 30 a cycle): an 8 MHz oscillator simulates slowly.

VERSION
TEP Crystal library V1.0 (Nov 2026). Devices CRYSTAL32KTEP and CRYSTALHC49TEP (TEPCRYSTAL.LIB /
TEPCRYSTAL.DLL). Demo sketch Crystal_Demo V1.0. Demo board: ARDUINO UNO V4.0 (TEP Arduino Library
V4.0) with its built-in serial monitor.