In this post we diagnose a PIR activated message player circuit, which was sent by Mr. Norman Kelley one of the dedicated followers of this blog for improvements. I have explained more about the design through the following discussions. Triggering Message Playback with a PIR Input I have been working on a project for about […]
Audio and Amplifier Projects
Simple 150 Watt Amplifier Circuit using Transistors
This 150 watt amplifier is designed to provide a full 150 watt peak to peak music power amplification over a 4 ohm loudspeaker. In this post I have explained how to make a simple 150 watt power amplifier circuit using a typical OCL design which ensures cheap layout and use of minimum components, with high […]
OCL Amplifier Explained
In the field of audio amplifiers OCL stands for Output Capacitor-Less Amplifier design. How it Works In this OCL type of amplifier topology or configuration, the power output stage is directly coupled to its preceding driver stage without coupling capacitors. The following figure shows a typical OCL amplifier output stage, as can be seen, the […]
Mp3 Player Using DF Player – Full Design Details
In this post I will show how to construct an Mp3 player using arduino and DFPlayer. The proposed article has two Mp3 player designs, one with push button control and another one with IR remote control. We will also take a look at DFPlayer (Mp3 player module) and its specifications. We all love music, we […]
5 Simple Audio Mixer Circuits Explained
The explained 5 circuits below are universal simple audio mixer circuits, that may be customized and upgraded to 5 channel or even 10 channel mixers, as desired by the user. Contributed by: Anil Rao. Stereo Audio Mixer The operation stereo audio mixer circuit shown below is straightforward: If a mic is “being used,” its output […]
Balanced Microphone Preamplifier Circuit
In this post I have explained about a simple Hi-Fi balanced microphone preamplifier circuit and also evaluate the calculations, specifications of the design through formulas. What is a Balanced Preamplifier A “balanced” amplifier or differential amplifier possesses not one but two distinct inputs and only the difference amongst these inputs is actually amplified. To elucidate […]