Circuit Project Electronic

Amplified Ear using BC547
Tuesday, November 18th, 2008

This circuit, connected to 32 Ohm impedance mini-earphones, can detect very remote sounds. Useful for theatre, cinema and lecture goers: every word will be clearly heard. You can also listen to your television set at a very low volume, avoiding to bother relatives and neighbors. Even if you have a faultless hearing, you may discover [...]

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Portable 9V Headphone Amplifier using NE5532
Saturday, November 15th, 2008

After several requests by correspondents, the decision of designing a 9V powered Headphone Amplifier was finally taken. The main requirement was to power the circuit by means of a common, PP3 (transistor radio) alkaline battery.
So, implementing a low current drawing circuit was absolutely necessary, though preserving a High Quality performance.
The appearance of the 5534 low-noise [...]

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Bench Amplifier with LM386
Monday, November 3rd, 2008

The circuit is based on the National Semiconductor LM386 amplifier. In the diagram above, the LM386 forms a complete non-inverting amplifier with voltage gain of x200.
A datasheet in PDF format can be downloaded from the National Semiconductor website. The IC is available in an 8 pin DIL package and several versions are available; the LM386N-1 [...]

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