The Three Fives Kit: A Discrete 555 Timer

Re-create one of the most iconic chips in electronics history. The Three Fives Kit from Evil Mad Scientist Laboratories is a faithful, functional transistor-scale replica of the classic NE555 timer IC — built up from individual resistors, 2N3904 and 2N3906 transistors on an oversized PCB shaped like a DIP-8 integrated circuit.

Designed by Eric Schlaepfer in collaboration with Evil Mad Scientist Laboratories, the kit ships as version 2.0 with anodized aluminium legs. Once assembled, you can connect to the terminal posts and build classic 555 timer and oscillator circuits — and unlike the chip version, you can probe what's happening inside the circuit.

Key Features

• Functional 555 Timer – Works in the majority of standard 555 circuit designs
• Discrete Transistor Construction – Built from individual resistors and transistors, not a monolithic IC
• Easy Through-Hole Soldering – No surface-mount components; approximately 1 hour to build
• Anodized Aluminium Stand – Version 2.0 IC leg stand with a premium finish
• Colour-Coded Terminal Posts – 8 stainless steel thumbscrew terminals (1 red, 1 black, 6 grey) for easy hookup
• Probeable Internals – Monitor signals inside the circuit that are hidden in a standard 555 chip
• RoHS Compliant – All materials including PCB and stand are lead-free

Specifications

• PCB Size: 132.5 × 80.6 mm (5.215 × 3.175 in), 2.54 mm thick
• Assembled Size: 132.5 × 99 × 43 mm (5.215 × 3.9 × 1.70 in) including stand and terminal posts
• PCB Finish: Extra-thick matte black solder mask with pre-fitted 8-32 threaded inserts
• Stand Material: Anodized aluminium

What You'll Need

• A soldering iron and solder
• Flush wire cutters
• Phillips head screwdriver

Ideal For

• Learning how the 555 timer works at the transistor level
• Desktop display and conversation piece for electronics enthusiasts
• Building classic timer and oscillator circuits at a visible scale
• Teaching analogue electronics concepts

Package Contents

• 1× Three Fives PCB with pre-fitted threaded inserts
• Resistors and transistors (2N3904, 2N3906)
• 8× Colour-coded thumbscrew terminal posts
• 1× Anodized aluminium IC leg stand
• Printed assembly instructions

Resources

• Datasheet (PDF)
• Assembly Instructions (PDF)
• Principles of Operation (PDF)
• Documentation Wiki
• 100+ Example 555 Circuits