Here is a nice linear power supply collection:
- 5V,6V,9V,12V 1A using IC 7805,7806,7809,7812 (including PCB)
- 0-30V / 1A using IC 741, 2N3055, 2N3565 (including PCB)
- 1.25-30V / 1A using LM317 (including PCB)
- 0-30V / 2A using IC 723, 2N3055 (including PCB)
- 0-30V / 5A using IC LM723 & 2N3055 (including PCB)
- 0-30V / 20A using LM338 (including PCB)
- 0-35V / 2A using IC LM723, 2N3055, BD140, A671 (including PCB)
- 0-50V / 2A using IC LM723, 2N3055, BD140, A671 (including PCB)
- 5V / 5A using 7805, Mj2955 for digital circuit (including PCB)
- 12V / 10A using IC 723,2N3055 (including PCB)
- 5V / 3A using IC LA5105 (including PCB)
- 13.8V / 5A using LM338 (including PCB)
>>> list continues…
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Prototype PCB Cost calculator – [Link]
MemPot is a controller circuit that records a variable resisor (e.x potentiometer) values sequence and then playback function outputs the same resistor values. It was developed by ”Dan Blackburn” and “Tuomo Tammenpää” as a control interface for sound generators. To be more specific a PIC 16F819 stores a sequence of values from the user turning the knob of a potentiometer and plays the same sequence back via serially controlled digital potentiometer (DS1267) chip. Furthermore the memory buffer size and the playback speed can be adjusted. Complete schematics and source code are included.
MemPot v1.0 - potentiometer with a memory – [Link]
ChaN has build a capacitance meter based on the intergration method. This method measures the time takes a capacitor to charge to calculate the capacitance. His circuit is using an Atmel AVR mcu and some calibration is needed. Full schematics and source code are included.
Digital Capacitance Meter - [Link]
Jos van Eijndhoven have designed a 3 channel fan motor controller based on PIC 16F676 microcontroller. Mcu reads temperature from sensors and outputs PWM modulated signal to each output so the speed of fan is controlled accordignly. Three on board potentiometers controls the start up temperature for each channel. The speed of fan is controlled linearly according to temperature and drops slowly when temperature goes down fast to avoid instability. For the output transistors BUZ72 are selected and temperature sensor is LM60. PIC code is written in C and compiled to hex using free CC5x compiler.
Three channel fan speed controller for PC - [Link]
The idea of this TDA7313 based audio processor was to create a circuit capable to control all basic audio settings with the use of buttons and a LCD screen. When this idea realized, this board was born! We talk about this incredible 3 channel audio processor that is capable to control Volume, Bass, Tremble, Channel Select, Input gain for selected channel, LF speaker attenuation, RF speaker attenuation, LR speaker attenuation, RR speaker attenuation. It can be embedded on every audio system, the possibilities are endless. Video demostration comes next.
A little talk about what TDA7313 offers:
TDA7313 audio processor have been used for more than ten years in the industry because of its simplicity, functionality and good parameters like low distortion, low noise. Chip is based on BIPOLAR/CMOS technology and can be used in various applications including car radios, Hi-FI, simple mixers.
TDA7313 chip has 3 external stereo inputs, that allows to multiplex three incoming sound sources, volume control with steps of 1.25dB, Treble and BASS control, Loudness function, Each of four outputs have distinct control that allows to balance outputs. Chip can be controlled via I2C (TWI) interface.
This is a simple circuit that helps you check the functionality of crystals. You simply connect the crystal, power the board and if the crystal is good a led is lighting.
Simple Crystal Tester – [Link]
That’s a very nice PIC Prototyping board based on 18F2550 USB enabled microcontroller. Author writes:
“The board features a USB port that can be used with a bootloader for easy programming. Five analog inputs are brought out (AN0-AN4) which can be used to read analog sensors, as well as the two CCP ports which can be used to control servos or other devices. A user LED is built in, using RA4. The onboard USART ports are brought out to a three pin header which can be used to talk to other microcontrollers, or to an RS232 device with a MAX232 level converter. The whole of PORTB is brought out to a header, as well as a pair of power headers. An ICSP header rounds out the board for programming the PIC.”
PIC Prototyping board 18F2550 – USB enabled – [Link]
On www.nuxie1.com i found a well designed function generator based on chip XR2206. This chip is a monolithic function generator integrated circuit capable of producing high quality sine, square, triangle, ramp, and pulse waveforms of high-stability and accuracy. The project’s page provide full schematics and pcb boards designed with Eagle. View details on the source site.
1MHz Function Generator based on XR2206 -[Link]
With this simple circuit you are able to control the speed of a DC fan according to temperature measured by a temp sensor. It’s an ideal addon for your PC cooling fans to eliminate produced noise.
On the first site two circuits are displayed. The first circuit is a simple version using LM317 and a temperature depended resistor to detect temperature. The voltage applyed to the fan is proportional to temperature. The second is a more advanced one using LM35 as temp sensor and four OPAMPs to achieve linear response of the output according to temperature measured.
On the second site you can find a Temperature controlled 12V dc Fan circuit using a Thermistor. All designs are selected for their simpicity, so the choise is yours!
Temperature controlled DC Fan – [Link]
Temperature-controlled 12V dc Fan - [Link]