Lead-Acid/SLA Battery Condition Checker - In July 2009 we presented an improved version of the Battery Zapper & Desulphator. Here we present the companion Battery Condition Checker. It gives more stable readings for all three main battery voltages (6V, 12V & 24V) than our earlier model, as well as giving a choice of test current pulse levels to suit batteries of different capacities. As a result, it?s now also suitable for testing sealed lead acid (SLA) batteries.__ SiliconChip
LED & Piezo On One Line using a PIC16c508 - Scroll to find this circiutOne of the simplest combinations is a LED and Piezo on a single drive-line as shown in fig: 1. These can be combined because the requirements of a LED are different to a piezo. A LED requires a constant HIGH for it to illuminate while a piezo requires a HIGH-LOW-HIGH waveform at approx 3kHz to produce a tone. __ Designed by Prepared Colin Mitchell
LED & Push Button On One Line using a PIC16c508 - Scroll to find this circuit # 2In this book, we show how to connect two and up to five or more push buttons on a single input line and generally you will not have any problems adding buttons to a project. But if you want to add a secret reset button (or a "cheat" button, for example) , it can be added across an existing LED as shown in fig: 3. __ Contact: Colin Mitchell
LED 9-Second Relay Timer - This circuit provides a visual 9 second delay using a 7 segment digital readout LED. When the switch is closed, the CD4010 up/down counter is preset to 9 and the 555 timer is disabled with the output held high. When the switch is opened, __ Designed by Bill Bowden
LED AM meter - Measures current up to 10A with selected 100mA, 10mA and 1mA resolutions.
LED Christmas Tree with 64 LEDs - The Holidays are once again upon us and we wanted to give our readers the edge in decorating this year. Continuing our all-digital-hardware theme to coincide with our Kickstarter for a Digital Electronics Course at PyroEDU, we have created an LED Christmas tree controlled entirely by digital logic __ Designed by PyroElectro
LED Clock with Timer & Solar Panel Regulator - This is a combination digital clock timer and solar panel charge controller used to maintain a deep cycle battery from a solar panel. The timer output is used to control a 12 volt load for a 32 minute time interval each day. Start time is set using 9 dip switches and ends 32 minutes later. __ Designed by Bill Bowden
LED display Digital Voltmeter - This digital voltmeter is ideal to use for measuring the output voltage of your DC power supply. It includes a 3.5-digit LED display with a negative voltage indicator. It measures DC voltages from 0 to 199.9V with a resolution of 0.1V. The voltmeter is based on single ICL7107 chip and may be fitted on a small 3cm x 7cm
LED Flasher - LED flasher with the LM3909 IC and runs from1.5-Volt battery. __ Designed by Tony van Roon VA3AVR
LED Lighting Effects - The original yoyo was equiped with 2 LEDs that lit up whendevice was spinning. I decided to add a micro to give it some extra pazazz. The trick here is to makeunit work without a power switch. The mercury switch is positioned so that it supplies power whenunit is spinning. After about 20 seconds, PIC shuts down in sleep modes, __ Designed by Luhan Monat-Mesa Arizona
LED Lighting For Dual-Filament Lamps - Before we describe how it’s done, note that we recommend that the result be checked as having sufficient brightness for a stop & tail-light application. That’s because the light output may be inadequate, depending on the tail-light lens and reflector assembly – so use any modified lamps with discretion! As shown, an additional diode (D1) […]
LED Lighting for Your Car - Replace your car's filament lamps with LED's for improved safety. There are several designs to build, all using high- brightness LED's.__ SiliconChip
LED Relay Timer - This circuit provides a visual 9 second delay using a 7 segment digital readout LED. When the switch is closed, the CD4010 up/down counter is preset to 9 and the 555 timer is disabled with the output held high. When the switch is opened, __ Designed by Bill Bowden
LED Strobe & Contactless Tachometer - This versatile LED Strobe & Tachometer can be used to observe and measure the RPM of rotating machinery. It offers three different measurement methods and the readout is via a 2-line LCD module.__ SiliconChip
Led Strobe & Tacho Pt.2 - Last month, we published the circuit of our new LED Strobe & Tachometer and showed how to build the main unit and the strobe light. This month, we describe the assembly of the optional Photo-Interruptor and IR Reflector Amplifier boards. We also describe how the unit is used.__ SiliconChip
LED Voltmeter - Measures voltages up to 199.9V with 0.1V resolution.
Let's Get Quizzical: a Quiz Game with a Difference - No more boring old buzzers for us...__ SiliconChip
Li-Ion Charger - PIC Project Lithium Ion batteries pack a lot of power by weight compared to other types. There are 2 things that need to be handled differently than NiCad on NiMH
: __ Designed by Luhan Monat, Mesa, AZ
Limiting Amplifier is Digitally Programmable - 06/04/98 EDN-Design Ideas To generate high voltages with proper insulation between "hot node" and rest of circuitry, a car ignition coil can function in place of a high-voltage transformer. se coils have voltage ratings of approximately 20 kV,. Design by V Manoharan, Naval Physical and Oceanographic Laboratory, Kochi, India
Line ReversalUsing a PIC16c508 - Scroll to find this circuit #4- If a device is connected between two output lines as shown in fig: 5, a program can be written so that the device sees a voltage reversal. When one output is HIGH the other is LOW and this is then reversed. __ Contact: Colin Mitchell
Linear Circuits for Digital Systems - Linear Technology AN31 __ Designed by Jim WilliamsFeb 2nd, 1989
Linears for Digital Systems - AN31 Subtitled "Some Affable Analogs for Digital Devotees, " discusses a number of analog circuits useful in predominantly digital systems. VPP generators for flash memories receive extensive treatment. Other examples include a current loop transmitter, dropout detectors, power management circuits, and clocks. __ Linear Technology/Analog Devices
Litter Box - PIC Project Not every new use of technology requires a microcontroller. This one uses a 12 volt computer fan from CompUSA, a snap close food box from Walmart, some PVC pipe from Home Depot, and a large plastic storage container from Big Lots. __ Designed by Luhan Monat, Mesa, AZ
LM3909 LED flasher - LED flasher with the LM3909 IC and runs from1.5-Volt battery. __ Designed by Tony van Roon VA3AVR
Logic ‘High’/’Low’ Indicator - This logic 'high'/'low' indicator circuit comprises two ICs. One is hex inverter IC 7404 (IC1) and the other is a bistable multivibrator built around timer IC 555 (IC2) . A logic probe...__ Electronics Projects for You
Logic analyzer pushes microcontroller to its limit - 12/07/00 EDN-Design Ideas A simple logic-analyzer design is compatible with all versions of Windows and pushes the PIC 18C252 chip to its speed limit to achieve a 1-MHz sampling rate (Figure 1) . The circuit can examine three channels of relatively low-speed logic signals that have infrequent, or sparse, transitions. The analyzer can record only 510 transitions per run, but a run can last as long as several minutes, if necessary. Applications include monitoring the I/O of an IBM keyboard or printer port, TI-calculator intercommunication, and serial (RS-232) signals Design by Tom Lyons Fisher, Inexpensive Systems, Huntingdon, PA, and Michael Deskevich, Juniata College, Huntingdon, PA
Logic circuits using discretes - There have been many times when I've been designing machinery controls where I have needed a logic function but only one so it's not worth using a quad logic gate. Here are some of the ways I use. Look carefully at them and you may gain a new perspective on logic and truth tables! __ Designed by Richard Torrens
Logic Family Voltage Translation - how to translate between TTL, 74xx, CMOS
, ECL, PECL, Low Voltage TTL, LVTTL, etc
Logic IC yields simple, wide-range timer - 08/01/97 EDN-Design Ideas You can use a 4060B binary counter/oscillator to make a simple, accurate, long-delay timer. The circuit offers longer times (milliseconds to hours] than you can achieve with common IC timers. A positive logic level at the input holds the counters in the reset state and the output in the low state. When the input goes low, the output goes high, forward-biasing D1 and "stalling" the oscillator Design by Harry Bissell Jr, Robotron Corp, Southfield, MI
Logic offers Complementary Switch Control - 12/06/01 EDN-Design Ideas The complementary-switch controller in Figure 1 uses a few inverter gates to provide drive signals for the complementary switches. Complementary-switch configurations find wIdeaspread use in synchronous-rectification circuits, charge pumps, full-bridge control circuits, and other circuits. The circuit in Figure 1 provIdeas not only a complementary drive signal but also a deadtime delay Design by Yen-Hsu Chen, Analog Integrations Corp, Hsinchu, Taiwan
Logic probe - This logic probe uses a single CMOS
IC and shows three logic conditions, High, Low and Pulsing. In addition if the probe input is neither hi or low (the high impedance state of tri-output logic IC's) then no LED's will light. Power from the logic probe is taken from the logic circui __ Designed by Andy Collison
Logic Probe uses Bicolor LED - 03/13/98 EDN Ideas - (File has several circuits, scroll to this one) A project posed the challenge of replacing existing analog potentiometers (used to set brightness and contrast levels]in video monitors with digitally controlled potentiometers. The different brands and models of monitors presented widely varying voltages across the potentiometers. The design. Design by Mark Shill, Burr-Brown Corp, Tucson, AZ
Logic PSU with OverVoltage Protection - A simple 5 Volt regulated PSU featuring overvoltage protection. __ Designed by Andy Collison
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