4 layers78 × 59 mm
2 layers34.7 × 12.2 mm
PWM Modulator
justharihere/PWM_ModulatorThis is an experimental PWM Modulator I developed while experimenting with NE555 timer ICs, datasheets, and learning PCB fab.
- Size
- 34.7 × 12.2 mm
- Copper layers
- 2
- Thickness
- 1.6 mm
- Parts
- 18
- Nets
- 10
- Pads
- 49
- Tracks, vias
- 96, 12
- Pours
- 1
- Routed
- Yes
- KiCad
- KiCad 9.0 (file 20241229)
- Created
- 29 Aug 2026
- Updated
- 30 Aug 2026
Overview
PWM Modulator is an open-source printed circuit board by justharihere, from the justharihere/PWM_Modulator repository on GitHub. It is a 2-layer board of 34.7 × 12.2 mm with 18 parts on 10 nets, routed with 96 tracks and 12 vias.
It is built around the NE555DR, CC0603KRX7R9BB104 and CC0603KRX7R9BB103, with the PH2.54-1X2P-H25, 3362P-1-103LF and RC0603FR-0715KL among its other parts. Its parts include 9 capacitors, 4 resistors and 2 ICs.
Main components
6
NE555DR
SOP-80℃~+70℃ 100kHz 4.5V~16V SOP-8 555 Timers / Counters ROHSUMWTimers / Counters
CC0603KRX7R9BB104
0603100nF 50V X7R ±10% 0603 Multilayer Ceramic Capacitors MLCC - SMD/SMT ROHSYAGEOMultilayer Ceramic Capacitors MLCC - SMD/SMTCC0603KRX7R9BB103
060310nF 50V X7R ±10% 0603 Multilayer Ceramic Capacitors MLCC - SMD/SMT ROHSYAGEOMultilayer Ceramic Capacitors MLCC - SMD/SMT
PH2.54-1X2P-H25
插件,P=2.54mm-40℃~+105℃ 1 1kV 1x2P 2.54mm 2.5mm 2P 3A 3mm 6mm Black Brass Gold Pin Header Through Hole 插件,P=2.54mm Pin Headers ROHSJXTCONNPin Headers
3362P-1-103LF
插件-3P,7x6.8mm1 10kΩ 500mW ±10% ±150ppm/℃ 插件-3P,7x6.8mm Potentiometers, Variable Resistors ROHSjieerruiPotentiometers & Variable Resistors
RC0603FR-0715KL
UncategorisedUnknown maker
README
README.mdVariable-Duty PWM Generator
A fixed-frequency, variable-duty PWM modulator built from discrete 555 timer ICs — a 1 kHz astable NE555 triggering a monostable NE555, with a potentiometer controlling pulse width. Designed in KiCad and fabricated through JLCPCB.
Designed and fabricated Summer 2026
Schematic
[SCREENSHOT: full schematic, exported from KiCad]
- Astable NE555 (U1) generates a fixed 1 kHz clock
- Clock triggers a monostable NE555 (U2), whose pulse width is set by a potentiometer-controlled RC network
- [Brief note on any supporting components — decoupling caps, output buffering, etc.]
PCB Layout
[SCREENSHOT: PCB layout view from KiCad — top copper / silkscreen]
[SCREENSHOT: 3D render, if you generated one in KiCad]
Board Photos
[PHOTO: bare fabricated board, front] [PHOTO: assembled board with components soldered] [PHOTO: board powered on / in use, ideally with a scope or LED showing output]
Specs
| Spec | Value |
|---|---|
| Astable frequency | 1 kHz |
| Duty cycle range | [fill in — e.g. 10%–90%] |
| Supply voltage | [fill in] |
| ICs | 2× NE555 |
| Design tool | KiCad |
| Fabrication | JLCPCB |
| Sourcing | LCSC (via KiCad LCSC plugin) |
Bill of Materials
| Part | Qty | Value/Part # | Cost | Notes |
|---|---|---|---|---|
| NE555 | 2 | — | — | Astable + monostable |
| Resistors | — | — | — | — |
| Capacitors | — | — | — | — |
| Potentiometer | 1 | — | — | Sets monostable pulse width |
| PCB (JLCPCB) | 1 | — | — | — |
Design Notes
- [Why this topology — e.g. why discrete 555s over a microcontroller PWM]
- [Any calculations for RC timing constants, if you want to show the math]
- [Any issues you ran into and how you solved them — e.g. component substitutions, layout revisions]
References
- [NE555 datasheet]
- [Any timing-calculation reference or app note you used]
About
[One-line repo description — also set this in the GitHub "About" sidebar, not just here]
Parts
18| Qty | Value | Footprint | References |
|---|---|---|---|
| 5 | CC0603KRX7R9BB104 | easyeda2kicad:C0603 | C1, C4, C5, C8, C9 |
| 2 | 0603WAF1002T5E | easyeda2kicad:R0603 | R2, R5 |
| 2 | CC0603KRX7R9BB103 | easyeda2kicad:C0603 | C2, C7 |
| 2 | CL10A106KP8NNNC | easyeda2kicad:C0603 | C3, C6 |
| 2 | NE555DR | easyeda2kicad:SOIC-8_L4.9-W3.9-P1.27-LS6.0-BL | U1, U2 |
| 2 | PH2.54-1X2P-H25 | easyeda2kicad:HDR-TH_2P-P2.54-V-M-4 | H1, H2 |
| 1 | 0603WAF1003T5E | easyeda2kicad:R0603 | R4 |
| 1 | 3362P-1-103LF | easyeda2kicad:RES-ADJ-TH_3362P | VR1 |
| 1 | RC0603FR-0715KL | easyeda2kicad:R0603 | R1 |
Questions
How big is the PWM Modulator PCB?
It measures 34.7 × 12.2 mm and has 2 copper layers, 1.6 mm thick.
What parts does the PWM Modulator use?
18 parts, built around the NE555DR, CC0603KRX7R9BB104, CC0603KRX7R9BB103 and PH2.54-1X2P-H25. The full list of its parts is on this page, with links to each part's symbol and footprint where PCBKit's library has them.
Where can I download the PWM Modulator KiCad files?
From the justharihere/PWM_Modulator repository on GitHub, at the commit this page was made from: the board is PWM modulator.kicad_pcb and its schematic PWM modulator.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the PWM Modulator design in my own project?
Its repository states no licence, so its author keeps all rights: ask justharihere before reusing the design.
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