Test UM3481 musical circuit

The M348X series IC is a mask-ROM-programmed multi melody generator , implemented by CMOS technology.It is designed to play the melody according to the previously programmed information and is capable of generating 16 songs with 3 instrument effects : piano, organ and mandolin. The device also includes a pre-amplifier which provides a simple interface to  the driver circuit. The M3481…

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Telephone misuse indicator

When the phone line is in idle condition (on hook), the full voltage of 48V DC from the exchange appears across the line. When the phone is engaged by lifting the hand set, the voltage across the line falls down to around 12V. Thus, under idle condition (48V), VR1 is adjusted to give a positive biasing voltage to the base of Q3. As Q3 conducts Q1 gets into reverse bias and stops conduction. If the phone is engaged, Q3 stops conducting due to voltage drop across the lines, and subsequently, Q1 and Q2 starts oscillating and beeping is heard. Thus, this circuit can be used as an indicator for telephone tapping and misuse by an unauthorized person.

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MIC PRE-AMPLIFIER

This project is a microphone pre-amplifier based on LM358. DESCRIPTION This is easy to construct microphone pre-amplifier project using compact electret condenser microphone. The pre-amplifier is important building block of many audio communication systems. Circuit has been built around Op-Amp LM358. Power supply : 5 to 12 VDC @ 10 mA Output: Gain Approx. 100 On-Board…

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Top 5 things to buy from Utsource

When it comes to electronic components supplier, Utsource is on the top of the most popular contenders. This website is the best professional purchasing sites in the electronic components field. One can find an extensive variety of electronic component products here. Among various high-quality products, Utsource is best known for its electronic components and devices.

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MAGNETIC FIELD SENSOR USING AD22151

Magnetic field sensor project using AD22151 IC from Analog Devices, The AD22151 is linear magnetic field transducer. The sensor output is a voltage proportional to a magnetic field applied perpendicularly to the package top surface. The sensor combines integrated bulk Hall cell technology and instrument technology to minimize temperature related drifts associated with silicon Hall…

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