My HobbiesElectronics
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Ever since my introduction to the fascinating world of electronics at high school, I never lost interest in this field of engineering, and I don't think I'll ever do. I have designed and built many circuits some of which I have listed below.

  • Signal Seeker
  • Intercom
  • Simple detectors
  • Counter
  • Op amp based circuits
Electronics is a very broad field as you can imagine, but right now my interest is in audio power amplifiers. If you interested in power amplifiers, I invite you try these amplifiers below. You can also find vey good amplifiers at some of these websites:

Sound Activated Audio power Booster

Don't let the 20 watts fool you. This amplifier gives a beefy performance especially with a good set of speakers.

The TDA2005/2004 i.c houses two amplifiers and these are configured in a :bridge" arrangement to deliver the maximum voltage

into the loud speaker from the rather low starting point of 12v. Hence for stereo use, two power booster i.c.s are required. Below is a circuit diagram for the system.

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One thing that you might immediately notice is that I don't have a decoupling capacitor at the output of IC1a. I initially had a capacitor but then I realised that the decoupled signal was way to small. Because the amplifier (IC1a) sits at about 2.5V at quiescent state, I decided to remove the capacitor; hence make use of this reference voltage. That is, without any signal, the output would sit at 2.5V, but if a signal is picked up, this voltage will go up; therefore setting the reference for the comparator at about 2.5V would guaratee a high from the comparator whenever a sound is picked up.