This circuit will turn on/off 12V DC fan or CPU fan when temperature above normal temperature.You can set turn on temperature by adjust VR1. This circuit use an NTC (Negative temperature coefficient)which is a thermistor is one in which the zero-power resistance decreases with an increase in temperature. So If temperature increase the voltage at pin 3 on LM311 will decreased .The resistance of NTC is about 10K at 25'c.
Posted on Thursday, April 21, 2011 • Category: Test and Measurement
The generator was build using XR-2206 function generator IC, which is capable to generate sine, square, ramp and pulse waveforms in frequency range of 0.01Hz to 1MHz. The amplitude and frequency is modulated by voltage (potentiometers). The example circuit from datasheet worked well.
Posted on Thursday, April 21, 2011 • Category: Headphone Amplifiers
This audio amplifier uses TDA7053 which is an integrated class-B stereo power amplifier in a 16-lead dual-in-line (DIL) plastic package. Which requires minimal amount of external parts. This might be good solution to all of those who have PC with integrated sound card into motherboard. The main problem is that outputs of such sound cards are for active acoustic systems, this means that speakers must have power amplifier built in. If you decide to connect a headphones sometimes it might be not enough to provide required sound level.
Posted on Thursday, April 21, 2011 • Category: AVR
This is an AVR ISP Programmer which is controlled via COM port. Signal levels of the RS-232C line is converted to the target level, so that target device can operate in entire range of the VCC. And also it can be used as an communication cable to communicate between host PC and target program (this is explained in the following section). This ISP adapter is sufficient to develop most of the AVR applications.
Posted on Wednesday, April 20, 2011 • Category: Amplifiers
So this time I decided to make pretty simple but powerful enough car audio amplifier. For this I’ve chosen quad bridge car audio amplifier TDA7384 which has four input and four output channels with power capability of 4x35W. As datasheets of TDA7384 says it is low distortion, low output noise, low external component count. Also has Stand-By function and Mute function. It has several protections like from output short circuit to GND or to Vs, capable to handle very inductive loads, thermal limiter, load dump voltage. TDA7384 is an AB power amplifier cased in flexiwatt25 (eagle library is included in project archive) package witch is designed for high end car radio applications. It allows rail to rail output voltage swing with no need of boot-strap capacitors.
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