Speaker/headphone amplifier | |
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This part of the bat detector is used to filter and amplify the relatively
weak signal from the detector in order to send it to a speaker or to
headphones.
The filter has the purpose of removing all unwanted high-frequency noise and
distortion products. The filter can be implemented by a cascade of simple RC circuits. The amplification is easily implemented with a LM386 (pdf) audio amplifier. Another part that I like to try out once, is the TDA7052 from Philips (DIP8). It uses the principle of two bridged amplifiers. That has the advantage that the speaker can be directly coupled to the IC, without any fat coupling capacitors. Also more power can be delivered to the speaker. The quiescent current is the same as for the LM386: 4 mA. LM386 amplifier![]() |
This page was last Monday, June 26, 2000 |