Content for 2N3904

2N3904

The 2N3904 is a common NPN bipolar junction transistor used for general-purpose low-power amplifying or switching applications. It is designed for low current and power, medium voltage, and can operate at moderately high speeds. It is a 200 mA, 40 V, 625 mW transistor with a transition frequency of 300 MHz, with a minimal beta, or current gain, of 100 at a collector current of 10 mA. It is used in a variety of analog amplification and switching applications.

Simple DIY FM Transmitter

“Ever wondered how come you can just simply tune in to your favorite FM Radio Channel. Moreover, ever had the curiosity of making your own FM Station on a specific frequency? Well if the answer is Yes to any of …

Dub Siren V3 - 555 Project

“Ok - so this is going to be my last dub siren build (maybe…). This new one is an extension on the others that I have built and is definitely the best and easiest version I have designed. So what is …

FM Stereo Receiver add-on for Raspberry Pi

“Simple FM stereo receiver based on QN8035 for Raspberry Pi. The QN8035 is a stereo FM radio receiver launched by the Quintic Corporation. Compared to other popular digital FM tuners (RDA5807, TEA5767, etc.), this tuner does not seem to be …

Arduino Telephone Caller ID Unit

“CLI, also known as Caller ID and calling number delivery (CND), is a service offered by the telephone service provider to customers to obtain the calling party number and date/time of the call. The service activation and information format …

DIY Solar Charge Controller

“Make your own adjustable voltage solar charger. A solar charger is a charger that employs solar energy to supply electricity to devices or batteries. Solar chargers can charge lead acid or Ni-Cd battery banks up to 48 V and hundreds …

Simple Joule Thief

“Wikipedia says : A joule thief is a minimalist self-oscillating voltage booster that is small, low-cost, and easy to build, typically used for driving small loads. This circuit is also known by other names such as blocking oscillator, joule ringer, vampire …

Yet Another Perpetual Pendulum

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Circuit Board for Making Freeform Circuit Sculptures

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Electric Puzzle Game

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Aiie! - an embedded Apple //e emulator

“A Teensy 4.1 running as an Apple //e Teensy 4.1 (600 MHz arm Cortex M7) running a full-speed Apple //e emulator. Because everyone needs one of these, right?”