Free Circuit Diagram

This is a circuit of board system monitoring for temperature and voltage condition. It uses the NE1617A. The NE1617A is a 2 channel temperature sensor. It can measure remote and internal sensor. It also supports up to nine devices per bus. The temperature data update is selectable from 125 ms to 16 seconds, if it [...]

The LM1894 is a stereo noise reduction circuit suitable for audio playback application. The DNR system is non-complementary, meaning that it does not require encoded source signal. The system is compatible with almost all prerecorded tapes and FM broadcasts. This noise reduction system uses  psycho-acoustic masking and an adaptive bandwidth filtering to achieve 10 dB [...]

In high fidelity (hi-fi) audio system, the harmonic distortion level is kept as low as possible. To make sure that the amplifier handle the sigal perfectly, the response of many hi-fi audio systems is designed beyond the audio range, include the handling capability to process infrasonic (below 20Hz) and ultrasonic (higher than 20kHz) signals. Although [...]

Feedback in public address amplifier is something that should be avoided. The ideal solution is by adjusting the microphone and the speaker position, but it’s not always possible in many situation. Using frequency shifter to change the output frequency 10Hz lower than the input frequency can solve the problem, but it’s too expensive for [...]

Many new computers now only has USB port, and this serial to USB adapter might be the only help for old devices that provides only RS232/COM Port. This serial adapter uses FT232 USB-RS232  converter IC from FTDI (Future Technology Devices International).  The main features of this USB serial adapter chip are: 384 [...]

You might think that hum noise is produced by electronic device with improper design, yes you’re right. And you might choose to solve the trouble maker, the source. You begin to check the grounding, the cabling, casing, and many more things you can do to eliminate the hum heard from your amplifier. You might [...]