555 Timer as an A/D Converter. :  Measure voltages accurately with a microcontroller using this simple circuit. Includes sample program for the Parallax Basic Stamp.    (electronic construction project added 2/06)

70W Class AB Hi-Fi Amplifier:  This project considers the development of a 70W Hi-Fi Power Amplifier for use as part of a Hi-Fi separates music system. The design is a fairly simple circuit topology, which is easy to understand and the author believes that the finished result sounds very nice indeed. The web posting is developed from an original design document available in pdf below. The detailed design issues are discussed in the pdf, while this posting discusses the more practical issues involved in producing th... (electronic construction project added 2/06)

AIU: Analog Interface Unit:  If you need to add simple data acquisition capabilities to your PC, then look no further than the Analog Interface Unit. The Analog Interface Unit (AIU) is a simple circuit that connects to a PC parallel port, and allows you to sample and output 8-bit analog signals under software control.... (electronic project added 11/05)

AN-702: Build a Direction-Sensing Bidirectional Repeater:  National Semiconductor - Application Note   (Circuit / schematic design added 6/06)

BookPC MP3 Player. :  A small computer running Linux with 12 volt power supply and wired remote control makes a great sound system for a car.    (electronic construction project added 2/06)

Build a Basic Stamp Lightning Activity Monitor:  Uses a Basic Stamp 2 to display the number of lightning strikes per minute on a row of 8 LEDs. Depending on the mounting configuration, the lightning sensor is capable of detecting lightning strikes greater than 50 miles away.  The strikes-per-minute method allows the users to not only determine the magnitude of the lightning activity, but also if the storm is approaching or traveling away. By monitoring the LEDs, increasing values indicate that the storms getting closer, while decreasing values (LEDs) indicate the storm is moving away.  (electronic construction project added 10/05)

Build a Direction-Sensing Bidirectional Repeater:  National Semiconductor - Application Note   (Circuit / schematic design added 6/06)

Build a precise DC Floating Current source:  08/108/05  EDN -- Design Ideas  /  (electronic project added 11/05)   Use a general impedance converter and resistors to develop a specialized current source.

Build a Precision Deadband Circuit:  02/20/03 EDN Design Ideas  /  (added 1/05)  Deadband circuits find applications in servo-control systems. A precision current source and a half-wave inverting rectifier form a positive deadband circuit (Figure 1). The REF01, IC1, is a precision 10V voltage reference. It forms a precision current source with the addition of a unity-gain buffer (IC2A) and resistor R1....

Build a simple one chip phototimer:  07/08/04 EDN Design Ideas  /  (added 1/05)      The author of this Design Idea needed to automatically switch on a lamp when it became dark and keep it on for a given time. He couldn't find an inexpensive device that satisfied the requirement. So he designed a phototimer from scratch based on the low-end, eight-pin flash microcontroller MC68HC908QT2 from Motorola.

Build a Transformerless 12V to 180V DC/DC converter:  07/08/04 EDN Design Ideas  / (added 1/05)  Some transducers for portable or automotive applications need accurately regulated, high-voltage bias and draw little current. To produce such high voltages from a low battery voltage, designers typically use switch-mode dc/dc converters—generally, flyback converters. These converters exhibit high efficiency at medium or high output power.

Build a UPS for USB devices:  04/11/02 EDN Design Ideas  / (added 1/05)  Portable systems often include circuitry that derives power from an external source, such as USB. When the system disconnects from the USB supply, a battery takes over and supplies current via a dc/dc converter. A diode-OR connection (Figure 1) offers the easiest way to ensure that the supply voltage doesn't sag during this switchover to the battery. ...

Build an adjustable high frequency notch filter:  02/06/03 EDN Design Ideas  /  (added 12/04)  Although you can obtain universal, resistor-programmable switched-capacitor filters that are configurable as notch filters, most cannot operate at bandwidths higher than 100 kHz. Further, the typically 16- to 20-pin packages do not include a continuous-time, antialiasing filter to prevent spurious signals from appearing at the output....

Build an Infrared Night Scope:  (Circuit / schematic design added 6/06)

Build the Lightning Bulb:  (electronic construction project added 2/06)

Build your own Bypass capacitor tester:  12/06/01 EDN Design Ideas  /  (added 1/05)  Most circuits use bypass capacitors and can deliver substandard performance if the capacitors have poor pulse characteristics. Few if any articles cover how to test bypass capacitors for pulse characteristics. The circuit in Figure 1 tests these characteristics. It charges the capacitor under test through 100 kU for approximately 1 msec and then discharges it through 10U for a... ...

Build your own joysticks:  (added (6/03)

Build Your Own Low Cost Fuel Cut Defencer:  This article describes a modification that, if misapplied, has the potential for causing early engine failure. The information presented in this article is correct to the best of the author's knowledge, but is not guaranteed in any way. Neither the author or Team FC3S can be held responsible for any damage to a car that occurs as a result of using this circuit, nor for failure of the circuit to perform as expected.  (electronic construction project added 10/05)

Build your own Superheterodyne Receiver:  08/01/96 EDN-Design Ideas / (Circuit / schematic design added 6/06)

Building a Jacob's Ladder:  (added 2/05)

Building a Simple LF Exciter:  (Circuit / schematic design added 6/06)