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.

DIY Portable Alarm System

“When I was a kid, there were several political murders in the ex-YU that involved people who had Surveillance Systems that mysteriously stopped recording during the event and resumed without an issue immediately afterward. Weird right? With no evidence …

Arduino Cranial Stimulator (Bio-BrainTuner)

“Cranial electro stimulation uses harmonic frequencies to help balance the brain’s chemistry. Cranial electro stimulation uses harmonic frequencies to help balance the brain’s chemistry. By connecting with the body’s control center, the brain harmonic frequencies provide wide-ranging …

100 LED Oscilloscope

“This is my next build using LED matrix’s. You may have seen my last one - 81 LED Chaser, well this project uses 100 LED’s and is an oscilloscope! Admittedly, the resolution isn’t great for checking measurements (it …

Measuring Circuit Delay for FPGA Timing using the ADP3450

“Using the ADP3450, this project measures amount of delay between asserting FPGA IO on base of NPN 2N3094 and LED illuminating on collector. Signal timing is a huge component in FPGA design, and while many tutorials demonstrate how to handle …

Build a Laser Harp From Scratch

“This is actually a really simple circuit, using just one hex-inverter chip and a handful of small, common components. Discover step-by-step how this circuit works by building it on breadboard first with a detailed guide. Finally, build the finished instrument …

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 …