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.
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:
- Signal Seeker
- Simple detectors
- Op amp based circuits
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
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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.