High Intensity Line Powered LED Flasher - There are times when you would like to generate an intensely bright flash of light using electrical power from the AC line. The circuit below can drive a one to three watt power LED with about 350ma of peak current. Since the circuit drives the LED with. . . Circuit by David Johnson P.E.-December, 2008 Hot AC Power Line Indicator - The circuit below is designed to detect when a power cable is active (hot) . When the flat sensor end of the device is held near an active AC line, the bright green LED on the top of the housing will glow. It is powered by a 3v CR2032 lithium coin cell. I . . . Hobby Circuit designed by Dave Johnson P.E.-May, 2005
Hot Water Tank Indicator - The idea for this project may have come to me in a flash of inspiration, and its a very simple way to check if a fuse has blown without removing it from its holder __ Designed by Andy Collison
Humidity Indicator & Controller - Presented here is a simple humidity indicator and controller. In industries such as textile, the change in moisture content has a direct impact on the properties of fabric, such as tensile...__ Electronics Projects for You
Improved Infrared Receiver with status led - 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 __ Contact: IQ Technologies
Incoming call indicator - It is a relatively simple circuit, with which we can have optical and sound clue, when we have telephone ring in the line of telephone. The calls in the line, are changed in pulses of frequency 400 HZ from the IC2, in exit 3. Then via the IC4, after they are strengthened at two times, they can be drive to the entry of amplifier and a loudspeaker, so that we hear the ring, in what level we want. The desirable level of sound __ Designed by Sam Electronic Circuits 8/01
Indicate DC Current Flow - The circuit below is a simple way to indicate when DC current is flowing through a wire. The circuit is designed so it will turn on a LED indicator light, whenever the voltage drop across a shunt resistor exceeds about 0.1volts. The value of the resist . . . Hobby Circuit designed by Dave Johnson P.E.-October, 2005
Indicate Health of Lithium-Ion Batteries - 05/14/09 EDN-Design Ideas A simple inexpensive circuit quickly indicates a battery pack's health Design by Fritz Weld, Friedberg, Germany
Indicates 120 VAC or 240 VA - C - Two LEDs indicate if a power line has 120vac or 240vac voltage on it . . . Hobby Circuit designed by David A. Johnson P.E.-January, 2007
Indicates a Low battery - 02/03/14EDN-Design Ideas It may seem a bit counterintuitive to power on an LED when a battery is already low, but this Design Idea does it with aplomb Design by James Wood
Indicates Automotive Electrical Voltage - When troubleshooting the 12v electrical system of an automobile, it is nice to have a simple voltage indicator tool instead of a voltmeter. This electronic circuit, hobby circuit is powered by two AA or even two N cells, which will provide enough energy . . . Hobby Circuit designed by David Johnson P.E.-July, 2006
Indicates Battery Charge Current - This circuit turns on a LED whenever it detects at least 25ma of battery charge current . . . Hobby Circuit designed by David A. Johnson P.E.-July, 2006
Indicates Battery Charging Current - Anyone who has ever had a shocking experience on an especially dry day is acutely aware of the kinds of high voltage that can be generated from a simple walk across a carpeted floor. Those same finger to metal sparks can destroy or disrupt sensitive elect . . . Hobby Circuit designed by Dave Johnson P.E.-January, 2011
Indicates when Power is Lost - Dave Campbell designed this clever circuit. It uses two neon lamps to indicate if power to a 120vac appliance had been interrupted. __ Designed by Dave Campbell, Boulder CO
Indicator features expanded scale - 02/21/02 EDN-Design Ideas Test equipment for a production line should be user-friendly (read "idiot-proof"] and should offer minimal test time. In many cases, the test fixture must give an operator only one answer pass or fail. Usually, two indicators assum Design by Abel Raynus, Armatron International, Melrose, MA
Indicator for Acceptable Voltage - I have used this circuit many times in custom test fixtures where a simple go-no go indication was needed. The circuit can also be used to adjust a particular voltage be within specific high or low limits. The three LEDs will indicate if the voltage is . . . Hobby Circuit designed by David Johnson P.E.-February, 2002
Indicator for Bad Light Bulb - This request came from a Discover Circuits visitor. He wanted to turn on a LED indicator light whenever a circuit detected a burned out tail/brake light on a car or truck. The circuit shown below uses a transistor switch, to detect current flowing through a low value resistor . . . Hobby Circuit designed by David Johnson P.E.-December, 2006
Indicator for Dynamic Limiter - NOTE
: Must register on this site __ Designed by Published in Elecktor July/Aug, 2010
Indicator Has "Electronic Lens" - 4-Sep-03 EDN-Design Ideas The method for implementing an extended-scale meter described in an earlier Design Ideas had a conceptual error The meter impedance must change continuously, not discretely as expressed (Reference 1]. You could achieve the desired result by using a digital potentiometer controlled by an input voltage via an appropriate interface Design by Abel Raynus, Armatron International Inc, Melrose, MA Indicator_Optical_Fiber - The concept was to have four germanium photodiodes along the front of a suitable plastic box. Each photodiode would have a narrow band optical filter placed in front so it would respond only to light in that specific narrow wavelength. A comparator circuit would monitor the light from each photodiode . . . Dave Johnson, Lubbock TX-DC Magazine - Issue 1 Sept 2009IR Remote LED Indicator Light - There are times when you would like to transmit a signal from one LED indicator light to second LED at another location. The circuit below works well for this application. It takes advantage of the fact that the internal infrared LED inside an opto-isolator. . . Circuit by Dave Johnson P.E.-December, 2008
Isolated indicator signals telephone line's status - 06/08/06 EDN-Design Ideas Micropowered circuit shows off-hook phone Design by Yongping Xia, Navcom Technology, Torrance, CA |