In this post I have explained the main datasheet and pinout details of the NPN transistor 2N3904 Introduction The transistor 2N3904 comes under the category of NPN small signal, low power, general purpose transistor, mainly applicable for switching and for signal amplification. It’s dynamic range may include a current handling capability of more than 100mA […]
Newly Updated Circuit Projects:
Simple Electronic Fuse Circuit
In this article we investigate a electronic circuit design which works like a conventional fuse for safeguarding any electrical system from overloads, over-current, short circuit and related fire hazards. However, the main advantage of this electronic fuse is that it does not require frequent replacements like mechanical fuses, instead it can be reset with a […]
DIY 100 Watt MOSFET Amplifier Circuit with PCB
MOSFET based amplifiers as we all know are outstanding with their sound qualities and they can easily beat the performance of other counterparts based on power transistors or linear ICs. Why use MOSFETs in Amplifiers Amplifiers based on mosfets are not always easy to design or make. Moreover after assembling a prototype, testing to perfection […]
Simple Programmable Timer Circuit
This programmable timer can be used for switching a load ON and OFF with two sets of time delays, which are programmable from 2 seconds to 24 hours independently. The delay timings are adjustable according to the users personal specs. The ON time delay and the OFF time delay are independently settable and this facility […]
Earthquake Sensor Circuit [Seismic Sensor]
The article shows an earthquake sensor circuit idea which incorporates an innovative way of detecting the minutest of shocks caused by a possible earthquake tremor. The circuit is so sensitive that it is able to detect tremor of 4 on the Richter scale, yet remains unaffected to loud sounds or irrelevant bangs or noises. Introduction […]
AC Light Dimmer Circuit
In this post I have explained through two examples how to build a simple110 V or 220 V AC light dimmer circuit for controlling light intensity with pot, using the principle of triac phase chopping. A 220V dimmer switch circuit is basically a triac/diac based AC mains voltage regulator circuit which can be used for […]





