2 layers121.9 × 77.5 mm SteppedAttenuator, the printed circuit board in 3D

SteppedAttenuator

hoofie2002/SteppedAttenuator

This project provides a schematic and PCB for a stepped attenuator

Size: 121.9 × 77.5 mm
Copper layers: 2
Thickness: 1.6 mm
Parts: 69
Nets: 85
Pads: 221
Tracks, vias: 205, 3
Pours: 2
Routed: Yes
KiCad: KiCad 6 (file 20211014)
Created: 21 Jun 2026
Updated: 24 Jun 2026

Overview

SteppedAttenuator is an open-source printed circuit board by hoofie2002, from the hoofie2002/SteppedAttenuator repository on GitHub. It is a 2-layer board of 121.9 × 77.5 mm with 69 parts on 85 nets, routed with 205 tracks and 3 vias.

It is built around the BC548. Its parts include 42 resistors, 6 diodes, 6 transistors, 6 switches and 5 connectors. It belongs with the AVR (ATmega, ATtiny) boards of this library.

Main components

BC548
TO-92TO-92 Bipolar (BJT) ROHSDDFBipolar (BJT)

README

README.md

This project provides a schematic and PCB for a stepped attenuator

Parts

Qty	Value	Footprint	References
6	1N4007	Diode_THT:D_DO-41_SOD81_P10.16mm_Horizontal	D1, D2, D3, D4, D5, D6
6	5.6K	Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal	R37, R38, R39, R40, R41, R42
6	BC548	Package_TO_SOT_THT:TO-92_Inline	Q1, Q2, Q3, Q4, Q5, Q6
6	G5V-2	Relay_THT:Relay_DPDT_Omron_G5V-2	K1, K2, K3, K4, K5, K6
3	1R	Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal	R4, R13, R18
2	110R	Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal	R20, R23
2	220R	Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal	R14, R17
2	430R	Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal	R8, R11
2	47R	Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal	R1, R6
2	5.1R	Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal	R31, R36
2	56R	Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal	R32, R35
2	6.2R	Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal	R19, R24
2	6.8R	Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal	R25, R30
2	62R	Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal	R26, R29
2	6R	Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal	R7, R12
2	7.5R	Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal	R16, R34
2	820R	Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal	R2, R5
1	1.8R	Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal	R22
1	10UF	Capacitor_THT:CP_Radial_D4.0mm_P2.00mm	C1
1	150R	Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal	R27
1	16R	Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal	R15
1	1UF	Capacitor_THT:CP_Radial_D4.0mm_P2.00mm	C2
1	240R	Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal	R33
1	3.6R	Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal	R10
1	3.9R	Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal	R28
1	4.7R	Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal	R3
1	51R	Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal	R21
1	8.2R	Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal	R9
1	Arduino_Nano_v2.x	Module:Arduino_Nano	U1
1	ENCODER	Connector_PinHeader_2.54mm:PinHeader_1x05_P2.54mm_Vertical	J5
1	I2C LCD	Connector_PinHeader_2.54mm:PinHeader_1x04_P2.54mm_Vertical	J2
1	LM78M05_TO220	Package_TO_SOT_THT:TO-220-3_Vertical	U2
1	Power	Connector_BarrelJack:BarrelJack_Horizontal	J1
1	SIG_IN	Connector_Coaxial:SMA_Amphenol_901-143_Horizontal	J3
1	SIG_OUT	Connector_Coaxial:SMA_Amphenol_901-143_Horizontal	J4

Questions

How big is the SteppedAttenuator PCB?

It measures 121.9 × 77.5 mm and has 2 copper layers, 1.6 mm thick.

What parts does the SteppedAttenuator use?

69 parts, built around the BC548. 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 SteppedAttenuator KiCad files?

From the hoofie2002/SteppedAttenuator repository on GitHub, at the commit this page was made from: the board is KiCad/KiCad.kicad_pcb and its schematic KiCad/KiCad.kicad_sch. PCBKit opens the board in the browser, with nothing to install.

Can I use the SteppedAttenuator design in my own project?

Its repository states no licence, so its author keeps all rights: ask hoofie2002 before reusing the design.

Category and platform

AVR (ATmega, ATtiny)

Project files

Show this board on your page

A live frame, for any web page

<iframe src="https://pcbkit.io/embed/boards/hoofie2002-steppedattenuator" title="SteppedAttenuator in PCBKit" width="100%" height="480" style="border:0;border-radius:12px" allow="fullscreen" loading="lazy"></iframe>

A picture

<img src="https://pcbkit.io/embed/boards/hoofie2002-steppedattenuator.jpg" alt="SteppedAttenuator" width="1200" height="900">

A picture that opens the board, for a README

[![SteppedAttenuator](https://pcbkit.io/embed/boards/hoofie2002-steppedattenuator.jpg?size=s)](https://pcbkit.io/boards/hoofie2002-steppedattenuator)

Source

Repository: hoofie2002/SteppedAttenuator
Board file: KiCad/KiCad.kicad_pcb
Commit: 215d6cc
Licence: Not stated

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