The Adafruit 555 PWM Output STEMMA is a fully assembled 555 timer board that generates an adjustable square-wave PWM signal — no breadboard wiring or external components needed. An onboard trimmer pot lets you tune the frequency across two selectable ranges: approximately 1.5 KHz to 25 KHz, or 1.5 Hz to 250 Hz.

The output is buffered by a 74HC1G04 inverter, capable of sourcing or sinking up to 12.5 mA — enough to drive piezos, modulate IR signals, generate audio tones, or fake a PC fan tachometer signal. Power the board from 3–12V DC; an onboard regulator caps the 555 and buffer at 5V, so the output stays at logic level regardless of input voltage.

Key Features

• Two Frequency Ranges – Selectable ~1.5 KHz–25 KHz or ~1.5 Hz–250 Hz
• Adjustable Output – Onboard trimmer pot for precise frequency tuning
• Buffered Output – 74HC1G04 inverter can source/sink up to 12.5 mA
• Wide Input Voltage – 3–12V DC with onboard 5V regulator
• STEMMA JST PH Connector – 3-pin 2 mm pitch for power, ground, and signal
• Optional Header – 0.1" spaced header pads if you prefer soldering
• No Microcontroller Needed – Standalone analogue signal generation

Ideal For

• PC fan tachometer signal emulation
• Driving piezos and buzzers
• Audio signal generation and testing
• IR signal modulation
• General-purpose square-wave generation

Package Contents

• 1× Adafruit 555 PWM Output STEMMA (assembled and tested)