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C# application controls simple ADC - 10/30/08, EDN-Design Ideas:  -  Control a simple, low-cost ADC with a PC's serial port.....(design idea added 08/09)

C-52 EVB Robot Controller  - Use a C-52 EVB for simple robot experiments. Build a simple two wheels robot with L293 H-Bridge driver and IR sensor. Write a C program controls robot tracked with black tape. (electronic circuit added 4/05)

Camera Remote Control System using Basic Stamp - (electronic circuit added 4/05)

CAN Node Using The Mcp2510 And Pic12c67x - Microchip Application Note Published 24-Feb-03  (app note added 6/06)

Cascaded UnManaged Repeater Applications - National Semiconductor Application Note  (app note added 6/06)

Cat Detector for a Cat Flap on a door. - This circuit uses one tuned coil for on the door and just a single wire loop on the animals collar. When the two coils come close together, it produces a signal that can cause a an LED to light and also trips a solenoid to unlock the door so it can open. Since all these doors are somewhat different, I leave  ….(circuit design added 3/08)

Ceiling Fanspeed Control - (electronic schematic / circuit added 2/05)

CFL Ballast for 26w/ Sprial Lamp 220Vac Input - The IRPLCFL5E reference design is an electronic ballast for driving 26W compact fluorescent lamps from 220VAC. The circuit provides all of  necessary functions for preheat, ignition and onstate operation of  lamp and also includes  EMI filter and  rectification stage. The circuit is built around  IR2520D Ballast Control IC.  (added 3/05)

Charge Coupled Bi-Directional Power Mosfet Relay - The circuit uses an inexpensive C-MOS inverter package and a few small capacitors to drive two power MOS transistors from a 12v to 15v supply. Since the coupling capacitor values used to drive the FETs are small, the leakage current from the power line into the control circuit is a tiny 4uA. Only about 1.5mA of DC is needed to turn on and off 400 watts of AC or DC power to a load. Published in Electronic Design, Nov. 8, 1990. ….(designed by David A. Johnson)

Church Bell Controller (Antonis Pontikakis) - This circuit is a church bell controller. Basic component is an ATmega32 microcontroller. At the circuit 2 24LC32 eeprom memories is being used, the 1st for internal standard melodies and the 2nd one is for user's compositions. This feature will be provided in the future. .….(circuit design added 08/08)

Circuit Automates Switch over between Battery and Source - 12/12/97, EDN-Design Ideas:  (design idea added 3/03)

Circuit Controls Brightness of Multiple Displays - 05/30/02, EDN-Design Ideas:     I recently needed to control nine seven-segment displays for a microcontroller's serial port. The complication I faced was the need to provide a continuous brightness adjustment for all the digits—from completely dark to fully bright. I couldn't easily use the obvious solution of a string of 74HC595 serial-to-parallel converters driving the segments.....(design idea added 6/06)

Circuit Controls intensity of reflex optical sights - 02/21/02, EDN-Design Ideas:  A popular category of aiming/pointing aids is the reflex, or "red-dot," sight. This system finds use in such diverse applications as astronomy, archery, and shooting. In the reflex sight, light from an internal source-typically a high-intensity red LED-reflects from a curved, transparent optical (reflex)element through which you view the target.....(design idea added 1/05)

Circuit Controls Isolated 12 Volt Stepper Motor - 09/26/96, EDN-Design Ideas:    -Allows full direction and step control of a12V, four-phase stepper motor from a5V, TTL/CMOS-compatible logic controller.....(design idea added 6/06)

Circuit Controls Microneedle Etching - 11/27/03, EDN-Design Ideas:  At its invention roughly two decades ago, STM (scanning tunneling microscopy)created a sensation because it was the first technology to make atomic-scale-resolution imaging a routine procedure. An essential requirement for the practical application of STM is some means for the reproducible fabrication of supersharp, atomic-scale needle tips.....(design idea added 1/05)

Circuit Controls Multiple Thermoelectric Coolers - 08/19/99, EDN-Design Ideas:  Optoelectronic and other components sometimes use a thermoelectric cooler and a thermistor for temperature control. A typical thermoelectric cooler.....(design idea added 2/06)

Circuit Controls Ratiometric or Simultaneous Power Up of Multiple Rails - 05/13/04, EDN-Design Ideas:  Many applications use FPGAs, AS ICs, or DSP chips, which usually require multiple voltage rails, typically two: the core voltage and the I/O voltage. The core voltage is usually lower than the I/O voltage. Guidelines for determining how to power up two or more voltage rails depend on the part and the manufacturer you use.....(design idea added 1/05)

Circuit Controls Slew for Stepper Drive - 03/14/97, EDN-Design Ideas:   The circuit in Figure 1 provides slewing control for stepper motors that you use in sophisticated applications, such as monochromator movements in optical experiments. The LM331 VFC plays a vital role in this circuit. The constant 10V dc from the IC9596 voltage reference routes to the VFC through the DG303 CMOS switch. The DG303's.....(design idea added 6/06)

Circuit Controls Stepper Motors - 01/08/04, EDN-Design Ideas:  Stepper motors are useful in many consumer, industrial, and military applications. Some, such as personal-transportation systems, require precise speed control. Stepper-motor controllers can be simple (Figure 1), but they require a variable-frequency square wave for the clock input. The AD9833 low-power DDS (direct-digital-synthesis)IC with.....(design idea added 1/05)

Circuit delivers dimming control for white LED driver - 10/28/04, EDN-Design Ideas:  The demand for power in color cell-phone handsets is constantly increasing. New applications steadily emerge, making it imperative to reduce power consumption in the design. Examination of usage data shows that more than 50% of the power consumed is in providing backlighting for the color screen. People use the phones for playing games and MP-3s and a multitude of other heavy-duty, multimedia f.....(design idea added 11/04)

Circuit Disconnects Load from Low Voltage Supply - 04/24/03, EDN-Design Ideas:  Power supplies often include a circuit that disconnects the load when the supply voltage drops too low, such as when a battery is nearly discharged. A p-channel MOSFET connected between supply and load is the typical approach. However, a 1.5V single-cell battery or other low-voltage supply is insufficient to fully turn on the MOSFET.....(design idea added 12/04)

Circuit forms DC Motor Switch with Brake - 01/10/02, EDN-Design Ideas:  controlling a small dc motor without speed control sounds like a trivial task; a switch or a relay should suffice. However, several problems accompany this approach. For one, the switch, because of the inductive load and the low starting resistance of the motor, tends to wear out prematurely (with all the related sparks and EMI problems).....(design idea added 1/05)

Circuit Generates Fan Speed Control - 03/21/02, EDN-Design Ideas:  Fan noise is becoming a significant issue as electronic equipment increasingly enters the office and the home. Noise is proportional to fan speed, and the airflow hence, fan speed necessary for cooling is less at low ambient temperatures. Because ambient temperature is lower than the upper design point most of the time, a fan can run slower,.....(design idea added 1/05)

Circuit Manages Power Up Sequencing - 10/31/02, EDN-Design Ideas:  Power sequencing poses a unique problem in power management. Because improper sequencing may cause damage to many types of processors, power-up sequencing of these devices is critical. Devices that may require power-up sequencing control include FPGAs, AS ICs, and DSP chips. These devices can require tracking I/O and core voltages.....(design idea added 1/05)

Circuit Measures Currents in DC Servo Motor - 12/06/01, EDN-Design Ideas:  The simple circuit design in Figure 1 lets you measure all components of a current flowing in a dc servo motor. The rectified output of the circuit uses ground as a reference, so you can measure the output by using a single-ended A/D converter. The current-sense resistor, R1, has a value of0.....(design idea added 1/05)

Circuit Protects System from Overheating - 11/08/01, EDN-Design Ideas:  The two-chip circuit in Figure 1 provides fan control and overtemperature warning and shutdown signals to protect systems from excessive heat. The circuit monitors the temperature of the pc board and the die temperature of a CPU, an FPGA, or another IC with an on-chip temperature-sensing transistor.....(design idea added 1/05)

Circuit Provides Bidirectional Variable Speed Motor Control - 05/16/02, EDN-Design Ideas:     During the development of systems that include small motors, a simple, bidirectional motor controller with speed adjustment may be helpful. Figure 1 shows such a controller. The circuit uses everyday components whose tolerances and ratings are unimportant as long as they sustain the required voltage, current, and power.. / (schematic / circuit added 11/03)

Circuit provides brownout control of 80C31 - 08/19/99, EDN-Design Ideas:  (design idea added 2/06)

Circuit Provides Class D Motor Control - 05/01/03, EDN-Design Ideas:  Class D audio amplifiers provide a dual benefit for battery-powered portable devices. They enhance battery life, and they produce much less power dissipation than do their linear cousins. Those features make Class D amplifiers ideal candidates for controlling speed and direction in small electric motors.....(design idea added 1/05)

Circuit Provides Efficient Fan Speed Control - 03/04/04, EDN-Design Ideas:  As Moore's Law plunges us into the realm of multigigahertz processors and PCs with gigabytes of RAM, engineers face the task of removing the heat that these state-of-the-art components produce. Cooling such systems poses a dilemma. If you optimize the fan size and speed for nominal operating conditions, the system is susceptible to failure when conditions deteriorate.....(design idea added 1/05)

Circuit Provides Laser Diode Control - 09/19/02, EDN-Design Ideas:  Laser diodes are sensitive to ESD, rapid turn-on currents, and overvoltage conditions. To address those problems, the simple laser-diode controller in Figure 1 has several functions. The first part of the circuit comprises an 8.2V zener diode, D1 that forms the heart of a constant-voltage source for the laser diode.....(design idea added 1/05)