2 layers116.8 × 30 mm
Type d
google/mozc-devices
Circuit diagrams and firmware source code for Gboard DIY keyboards
14 parts3kApache-2.0
2 layers38.1 × 40.6 mm
Lex cap charge discharge demo single
alexhunsley/cap-funEducational tiny circuit for capacitor charge + discharge with LED
- Size
- 38.1 × 40.6 mm
- Copper layers
- 2
- Thickness
- 1.6 mm
- Parts
- 14
- Nets
- 6
- Pads
- 24
- Tracks, vias
- 25, 0
- Routed
- Yes
- KiCad
- KiCad 9.0 (file 20241229)
- Created
- 17 May 2025
- Updated
- 5 Jun 2025
Overview
Lex cap charge discharge demo single is an open-source printed circuit board by alexhunsley, from the alexhunsley/cap-fun repository on GitHub, published under the MIT licence. It is a 2-layer board of 38.1 × 40.6 mm with 14 parts on 6 nets, routed with 25 tracks and 0 vias.
Its parts include 4 connectors, 2 resistors, 2 switches, 1 capacitor and 1 diode.
README
README.mdcap-fun
I made this to try out KiCad, see blog post and follow-up.
This is a small educational circuit for demonstrating how capacitors work:
- insert an electrolytic capacitor (I suggest
1000uF) into the cap header (longer leg goes next to the+symbol) - insert a 3mm red LED into the LED header (longer leg goes next to the
+symbol)
Now hold down the discharge push button. If the cap has charge, the LED should light and fade as the cap discharges.
If you want to be able to charge the cap, connect the +V and GND pads to a DC power source (5V suggested), and the charge push button will charge the cap while it is held down.
More info at blog post.
Footnotes
- the cap voltage rating doesn't matter much because it can only charge up to the voltage the power supply provides
Parts
14| Qty | Value | Footprint | References |
|---|---|---|---|
| 4 | MountingHole | MountingHole:MountingHole_2.2mm_M2 | H1, H2, H3, H4 |
| 2 | Conn_01x01_Socket | Connector_PinSocket_2.54mm:PinSocket_1x01_P2.54mm_Vertical | J3, J4 |
| 1 | +5V | TestPoint:TestPoint_THTPad_2.5x2.5mm_Drill1.2mm | J1 |
| 1 | 1000uF | Capacitor_THT:CP_Radial_D10.0mm_P5.00mm | C1 |
| 1 | 10K | Resistor_THT:R_Axial_DIN0204_L3.6mm_D1.6mm_P7.62mm_Horizontal | R1 |
| 1 | 330 | Resistor_THT:R_Axial_DIN0204_L3.6mm_D1.6mm_P7.62mm_Horizontal | R2 |
| 1 | 3mm red LED | LED_THT:LED_D3.0mm | D1 |
| 1 | GND | TestPoint:TestPoint_THTPad_2.5x2.5mm_Drill1.2mm | J2 |
| 1 | charge | Button_Switch_THT:SW_PUSH_6mm_H4.3mm | SW1 |
| 1 | discharge | Button_Switch_THT:SW_PUSH_6mm_H4.3mm | SW2 |
Questions
How big is the Lex cap charge discharge demo single PCB?
It measures 38.1 × 40.6 mm and has 2 copper layers, 1.6 mm thick.
What parts does the Lex cap charge discharge demo single use?
14 parts. 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 Lex cap charge discharge demo single KiCad files?
From the alexhunsley/cap-fun repository on GitHub, at the commit this page was made from: the board is lex_cap_charge_discharge_demo_single.kicad_pcb and its schematic lex_cap_charge_discharge_demo_single.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the Lex cap charge discharge demo single design in my own project?
Its repository publishes it under the MIT licence: you may reuse it on that licence's terms (keep the author's notice, and for a copyleft licence share your changes alike).
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