3 Channel 8 Bit EEPROM DAC with DS Interface This device provides three channels of 8 bit pulse-width modulation.  Output pulse duty cycle ranges from 0 to 255/256 in 255 steps.  DACs may be loaded by the DS interface.  DAC values may also be copied into the on-chip EERPOM and then automatically be loaded into the DACs when power is applies, making it useful for automatic set up of circuits that do not contain microcontrollers.  This replaces more expensive EEPROM DACs and EEPROM pots in many applications, owing to its use of a small area high volume integrated circuit microcontroller.  Additionally, one page of 16 bytes of on-chip EEPROM storage is accessible via the DS interface.   __ Designed by Dick Cappels

3-Input Supply Powers 3.3V Portable 04/13/95 EDN-Design Ideas The single-ended primary-inductance converter in Fig 1 accepts input voltages ranging from 3 to more than 6V and produces a regulated 3.3 V, 200-mA output.  The converter accepts an input voltage from three sourcesa 5V dc wall cu Design by Len Sherman, Maxim Integrated Products, Sunnyvale, CA

3-State Switch Interface Uses One Microcontroller Pin 02/21/08  EDN-Design Ideas A single microcontroller I/O pin senses the state of a three-position switch Design by Kartik Joshi, Netaji Subhas Institute of Technology, New Delhi, India

3v PC Adaptor Plug this circuit into the available USB output port of your PC to get 50mA, 3V DC.  So it can be used to recharge, for instance, two NiCd cells   (1.2Vx2) of...__ Electronics Projects for You

3-Wire Serial LCD using a Shift Register HD44780 based character LCDs require at least 6 I/O lines from microcontroller to display data.  Therefore, they are not suitable for low-pin microcontrollers like PIC12F series microchips.  In this project, I am going to show how to __ Designed by Rajendra Bhatt

4 Ch Digital Logic Analyzer & 5 Ch Digital Oscilloscope in Parallel Port This is one of the simplest circuit for a PC parallel port based DLA.  The circuit is mainly used to protect the port which is fabricated on the otherboard itself.  The IC 74LS04 is an inverter and acts as a buffer.  The Zener is used for undervoltage and overvoltage protection.  If a voltage > 5V appears on the input, The buffer will not transmit this voltage to the PC.   __ Designed by Huzaifa S. Sidhpurwala, India

4-Channel Digital Logic Analyzer & 5 Channel Digital Oscilloscope by using PC Parallel Port This is one of the simplest circuit for a PC parallel port based DLA.  The circuit is mainly used to protect the port which is fabricated on the motherboard itself.   __ Designed by Huzaifa S. Sidhpurwala, India

5 Watt Universal Input Dual Output Isolated TNY266 This design kit is a 9 V, 0.33 A, 3 W output and universal input power supply utilizing the TNY264P.  For evaluation, a fully built and tested prototype (EP14) can be found within the Design Accelerator Kit, DAK-14.  

555 based beeper-loading from Commodore computer tape drive A while ago at the comp.sys.cbm newsgroup (yes I'm still typing in 2014, you new-fangled web forumers), a post was made asking if the schematic was available for the "PET Beeper", a device made in the 70s for the Commodore PET computer. __ Designed by Kevin Koster

56K RF Modem This is a prototype of the WA4DSY 56KB RF modem.  It is intended for use on amateur packet radio networks.  The modem generates RF in the 28 to 30 mhz range and requires and linear transverter to convert the signal to a UHF or microwave ham band.  The digital interface is synchronous serial.  The modem supplies TX and RX clocks.  For more details see the various links below.   __ Designed by Dale Heatherington's Ham Radio, Electronics and Robotics Web Site

5V power supply teams low-dropout regulator, charge pump 8-Jan-04 EDN-Design Ideas Auxiliary power of 3.3V is replacing the 5V auxiliary power that "silver boxes" supply in most computer systems, but some circuits still require a 5V supply.  Such systems impose the messy task of creating a central 5V auxiliary supply from the 3.3V auxiliary supply and then routing 5V power throughout the motherboard Design by Jim Christensen, Maxim Integrated Products, Sunnyvale, CA

7 segment rolling display using PC It is very interesting and convenient to be able to control everything while sitting at your PC terminal.  Here, a simple hardware circuit and software is used to interface a 7-segment based rolling display.  The printer port of a PC provides a set of points with some acting as input lines and some others as output lines.  Some lines are open collector type which can be used as input lines.  The circuit given here can be used for interfacing with any type of PC?s printer port.

8 Channel LPT relay board Channel Relay Board is a simple and convenient way to interface 8 relays for switching application in your project.  

8 Channel PWM Code AVR Controllers This article is about a software controlled, parallel port-interfacing 8-channel Pulse-Width-Modulated fan controller __ Designed by Dick Cappels

8 x 8 Audio Video Switch 8 channel switch.   __ Designed by Peter Jakab

80186 timer pins provide general I/O 08/01/98 EDN-Design Ideas   (File has several circuit ideas.  Scroll to find this one.) Intel's   (www.intel.com]) 80186 is a highly integrated mP common in embedded applications.  It combines 15 to 20 common iAPX86 system components, such as a DMA controller, an interrupt controller, timers, a clock generator, a bus i Design by Sk Shenoy, NPol, Kochi, India 

8051 Development System Board This is the complete schematic for the development board.  Address and Data bus wires are drawn separately   (not in a bus), so that it's easy to color over them on a printout, if you choose to manually connect the wires.  It really is easier to buy a bare circuit board, though. __ Designed by Paul Stoffregen

8051SBC V1.0 (Single Board Computer) I decided to rename C52EVBto be 8051SBC.  Since the cpu can be any 8051 compatible chips with 40-pinDIP package.  The old day chips, say 8031, 8751, 8032 or the new chips, 89C51, 89C52, 89C51RD2 can be used without any problem.  Some may thinkthat your old chips were useless, now you can use it for many projects.  The monitor program of new 8051SBC was placed at external 32kB EPROM __ Designed by Wichit Sirichote

89c2051proto Board This single sided proto board provides an economical solution for developing and testing the projects around Atmel 20 pin series u-controllers   (89Cx051 & AVR).   __ Designed by Wichit Sirichote

89s52 Project Board Simple 89S52 board for student projects __ Designed by Wichit Sirichote

8A Regulated Power Supply for 13.8V BR1 can be a bridge rectifier or four diodes   (10A) with a 100 PIV rating.  A 10, 000uF/50V electrolytic capacitor completes the filtering of the 28.8V.  Yep, C1 is a real clunker.  You can use larger if you like, just watch it when you power up.  Without a 'power-up' delay circuit of sorts it will probably blow-up the 723 if the capacitor   (C1) is too-large __ Designed by Tony van Roon  VA3AVR

8-way relay interface board for PC parallel printer port This is a general purpose serial port infrared receiver.  With the help of appropriate software   (see below) you can control different functions of your pc from a distance.  For example you can control your home cinema settings   (volume, play, pause, stop etc), your winamp etc.   __ Designed by Vassilis Papanikolaou

9 Channel PWM Code AVR Controllers This article is about a software controlled, parallel port-interfacing 8-channel Pulse-Width-Modulated fan controller __ Designed by Dick Cappels

9 pin (Female) Nullmodem Cable Circuit only, no circuit description included.   __ Designed by Tony van Roon  VA3AVR

9600 Baud Packet Radio Modem The conventional packet VHF/UHF radio data rate is 1200 baud because all TNCs provide an internal modem for this speed, and the two-tone AFSK audio spectrum suits unmodified voiceband radios comfortably.  However all TNCs can generate much higher data rates, and most FM radios have an unrealised audio bandwidth of some 7-8 kHz or more.  So in many cases 9600 baud radio transmission is entirely practical with them. __ Designed by James Miller G3RUH