Posted on Friday, March 11, 2011 • Category: Battery Chargers
Microchip announced the expansion of its analog power-management family with the MCP73831 battery charger, a fully-integrated, single-cell, Li-ion/Li-Polymer charge-management controller.
Tiny 500mA linear charge management controller can be powered directly from the USB port. Includes integrated pass transistor, current sense and reverse-discharge protection, the MCP73831 charger reduces the number of components needed for battery-charger designs. Its highly accurate, pre-set voltage regulation (maximum accuracy 0.5 per cent to 0.75 per cent) results in more fully charged batteries and extended battery life.
Since the MCP73831 charge-management controller includes a pass transistor, current sense and reverse-discharge protection on a single chip, it reduces the number of system components needed for battery-charger designs, which, added Microchip, lowers overall system costs.
Posted on Friday, March 11, 2011 • Category: Amplifiers
20W TDA2005 stereo amplifier for all suitable applications like amplifying medium power speakers. It is suitable for car use but before, the power supply must be choked with at least 150mH and it must give up to approximately 6 to 7 amps during the upstream performance.
Posted on Tuesday, March 8, 2011 • Category: LED
This code is for a simple RGB LED controller for 1 RGB LED using a PIC12F675 (or PIC12F629). The pattern is determined by the data in the EEPROM. When the PIC needs a new target for the PWM, it loads it from EEPROM. Pin 4 (GP3) is pulled high because it is used to switch between displays. Please see the source code for more information; the structure and design is commented. The operation of the controller is very simple and so is the wiring.
Posted on Monday, March 7, 2011 • Category: Amplifiers
Article about building Marshall 200W Leach Amplifier. For many years I looked for construction of HiFi amplifier wit a good parameters, enough power reserve and simple construction. I built a couple of amplifiers with integrated circuits MBA810, TDA2005, LM3886, but I was disappointed by their output quality and noise. I decide to built a classic construction with discrete components and bipolar transistors. Construction from Mr. Dudek was interesting, but I didn't like used components and complexity. All of my requirements satisfied construction of the Leach Amp. Circuit author publicates in a February 1976 in american journal. From these days circuit was not practically changed. Little changes are descripted on authors page.
Posted on Saturday, March 5, 2011 • Category: LED
The implementation of a RGB LED fader using 555 timer and 4029 digital IC is the objective of this project.
During the operation, the RGB LED is continuously cycled through the colors of the rainbow where the speed at which the colors change is adjustable. The switch between the different colors makes the effect very noticeable while a more relaxed effect happens when the colors fade into each other. These two options can be selected on this device.
The pulse generator based form a standard 555 timer is formed by IC1, C1, R4, R5, and VR1. The frequency of which, and hence the speed of the effect, as adjusted using the pre-set VR1. The pulses are fed into IC2 which is a 4029 binary counter whose outputs continuously count in a binary progression between 1 to 7. The transistors Q1, Q2, and Q3 are being driven by these outputs which in turn control each of the three colors of the RGB LED.
By passing through an RC network, the pulses are shaped before they reach their respective transistors. The fading effect between the colors or abrupt changing is produced by this shaping.
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