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1.5V LED Flasher - schematic only, no circuit description at this time __ Designed by Andrew R. Morris 1.5V LED Flasher Oscillator - The 8-lead plastic mini-DIP LM3909 IC was developed by National Semiconductor in the mid 'seventies of the past century. It was a monolithic oscillator specifically designed to flash Light Emitting Diodes. By using the timing capacitor for voltage boost, it delivered pulses of 2 or more volts to the LED while operating on a supply of 1.5V or less. The circuit was inherently self-starting, and required addition of only a battery and capacitor to function as an LED flasher __ Contact: Flavio Dellepiane, fladello @ tin.it
1.5v LED Flasher Version A - Many published circuits that flash LEDs need 3 volts or more. This circuit uses only a single inexpensive C-MOS IC and flashes the LED for a full year on a single 1.5 volt AA alkaline battery cell. The circuit uses a charge pump technique to provide. . . Circuit by Dave Johnson P.E.-June, 2000
1.5V LED Flashers - The LED flasher circuits below operate on a single 1.5 volt battery. The circuit on the upper right uses the popular LM3909 LED flasher IC and requires only a timing capacitor and LED. The top left circuit, designed by Andre De-Guerin illustrates using a 100uF capacitor to double the battery voltage to obtain 3 volts for the LED. Two sections of a 74HC04 hex inverter are used as a squarewave oscillator that establishes the flash rate while a third section is used as a buffer that charges the capacitor in series with a 470 __ Designed by Bill Bowden
1.5V Touch Activated Switch - A single 1.5v silver oxide button cell powers this complete touch activated switch circuit for 5 years. It features both a normally open and a normally closed set of solid-state switch thermals. It also has an adjustable sensitivity, which can be set for a touch capacitance change as small as 1 picofarad.. . . Circuit by David A. Johnson P.E.-January, 2002
10 Channel LED Sequencer - The 4017 is a CMOS
decade counter with 10 decoded outputs. Inputs include a clock (pin 14) , a reset (pin 15) , and a clock inhibit (pin 13) __ Designed by Bill Bowden
10 Channel Light Controller - A 10 channel light controller using PWM/ up to 1a per channel at 12v __ Contact: P. Townshend EduTek Ltd
10 LED Chaser - I don't know why, but people like blinking lights. You see LED chasers everywhere, in TV shows (Knight Rider) , movies, and store windows. This schematic is my version of a simple 10 LED chaser. There is no 555 timer used because __ Designed by Aaron Cake
10 LED Sequencer - Schematic only, text in Finnish
10 LED Sequential Flasher using Low Powr - A while back I posted a flasher circuit which flashed 10 LEDs sequentially. That circuit was powered by four AA alkaline cells. The circuit below operates much the same way but has been modified to run from a single 3v CR2032 lithium coin cell. . . Circuit by David Johnson P.E.-April, 2011
10 Stage LED Sequencer - The 4017 is a CMOS
decade counter with 10 decoded outputs. Inputs include a clock (pin 14) , a reset (pin 15) , and a clock inhibit (pin 13) __ Designed by Bill Bowden
10 Stage Light Sequencer - schematic only -- flashes 10 low voltage bulbs, operates at10-25-Volt voltage, in PDF format, text in Finnish
10 to 100 LED Sequencer using a Matrix - The circuit above illustrates using a 10x10 matrix to sequence up to 100 LEDs with just three ICs and 20 transistors. The two 4017 decade counters control the 10 rows and 10 columns so that one LED is selected depending on the output of the decade counters. The LED circuit is drawn showing 25 LEDs and 10 transistors but can be expanded up to a 100 __ Designed by Bill Bowden
12 Stage Neon Sequencer NE 2/NE 51 - This circuit is similar to the LED clock using 12 neon indicator lamps instead of LEDs. It operates from 2 high capacity ni-cad cells (2.5 volts) which keep it going for a couple weeks. High voltage (70 volts) for the neon lamps is obtained from a small switching power supply using a 74HC14 Schmitt trigger squarewave oscillator, high voltage switching transistor __ Designed by Bill Bowden
12 to 100 LED Sequencer using a Matrix - The circuit above illustrates using a 10x10 matrix to sequence up to 100 LEDs with just three ICs and 20 transistors. The two 4017 decade counters control the 10 rows and 10 columns so that one LED is selected depending on the output of the decade counters. The LED circuit is drawn showing 25 LEDs and 10 transistors but can be expanded up to a 100 __ Designed by Bill Bowden
12 V Florescent lamp driver - Here is a simple and effective circuit for driving florescent lamps from a 12 V supply. The circuit is nothing but consists of an oscillator, a MOSFET switch and a step-up transformer for driving the florescent lamp. The IC1 TLC555 is __ Designed by Radio LocMan
12 Volt DC Fluorescent Lamp Driver - This fluorescent lamp driver uses a normal 120 to 6V step-down transformer in reverse to step12V to about350-Volt to drive a lamp without need to warm filaments. __ Designed by Aaron Cake
12 Volt fluorescent lamp drivers - Three schematics of 12 V drivers for 2, 8 and 20 Watt, plus a lot of explanations about fluorescent tubes. Use the drivers for camping, emergency, boating, etc. __ Designed by Manfred Mornhinweg
12 Volt Knight Rider LED display - 12 Volt Knight Rider, "Look-A-Like", Lighting Systems Revised "JAN.2, 2008" (Errors on Knight-3, Corrected) __ Designed by G.L. Chemelec
12 Volt Lamp Dimmer (using a pot) - Here is a 12 volt / 2 amp lamp dimmer that can be used to dim a standard 25 watt automobile brake or backup bulb by controlling the duty cycle of a astable 555 timer oscillator. When the wiper of the potentiometer is at the uppermost position, the capacitor will charge quickly through both 1K resistor __ Designed by Bill Bowden
12 Volt Lamp Fader (LEDs or incandescent) - This circuit is similar to the "Fading Red Eyes" circuit (in the LED section) used to fade a pair of red LEDs. In this version, the lamps are faded by varying the duty cycle so that higher power incandescent lamps can be used without much power loss. The switching waveform is generated by comparing two linear ramps __ Designed by Bill Bowden
12 Volt Lite/Dark Lamp Switch - Often, for certain low voltage lighting systems; you would like to turn off the lights during the bright light of the day. Most commercial day/night switches are designed for AC lighting. The circuit below was designed for a 12v DC system. But, it could be modified for other voltage as well. It uses an inexpensive phototransistor as the light detector. . . . Hobby Circuit designed by David Johnson P.E.-June, 2008
12 Volt Strobe - Strobes are useful devices for seeing fast moving components freeze or just as lighting effects. Unfortunately for a really good result you need to use a Xenon flash tube which can produce intense brief discharges of light but it needs high trigger voltagesupwards of 4KV! __ Designed by Phil Townshend 2009
12 Volt Strobe, Coil Driven - This circuit will give provide a Good Strobe Effect for a variety of
Portable Uses. Nominal current draw is "up to about" 1 amp at 12 volts. Depending on value of capacitor on pin 2 of the 555 and the particular choke that is used. The .01 cap on pin 2 of the 555 may be slightly changed in value to optomize the output drive to the 22 mfd capacitor. __ Designed by G.L. Chemelec
120 VAC Lamp Chaser using Solid State Relays - This circuit is basically the same as the 10 channel LED sequencer with the addition of solid state relays to control the AC lamps. The relay shown in the diagram is a Radio Shack 3 amp unit (part no.275-310) that requires 1.2 volts DC to activate. No current spec was given but I assume it needs just a few __ Designed by Bill Bowden
120 VAC Lamp Dimmer - The full wave phase control circuit below was found in a RCA power circuits book from 1969. The load is placed in series with the AC line and the four diodes provide a full wave rectified voltage to the anode of a SCR. Two small signal transistors are connected in a switch configuration so that when the voltage on the 2.2uF __ Designed by Bill Bowden
120 Volt AC Lamp Chaser using Solid State Relays - This circuit is similar toLED clock using12 neon indicator lamps instead of LEDs. It operates from2 high capacity ni-cad cells (2.5 volts) which keep it going for a couple weeks. High voltage (70 volts) forneon lamps is obtained from a small __ Designed by Bill Bowden
120 Volt AC Lamp Dimmer Full Wave SCR - The full wave phase control circuit below was found in a RCA power circuits book from 1969. The load is placed in series with the AC line and the four diodes provide a full wave rectified voltage to the anode of a SCR. Two small signal transistors are connected in a switch configuration so that when the voltage on the 2.2uF capacitor reaches about 8 volts, the transistors will switch on and discharge the capacitor through the SCR gate causing it to begin conducting. The time delay from the beginning of each half cycle to the point where the SCR switches on is controlled by the 50K resistor which adjusts the time required for the 2uF capacitor to charge to 8 volts. As the resistance is reduced, the time is reduced and the SCR will conduct earlier during each half cycle which applies a greater average voltage across the load. With the resistance set to minimum the SCR will trigger when the voltage rises to about 40 volts or 15 degrees into the cycle. __ Designed by Bill Bowden
120VAC Lamp Chaser using Solid State Relays - This circuit is basically the same as the 10 channel LED sequencer with the addition of solid state relays to control the AC lamps. The relay shown in the diagram is a Radio Shack 3 amp unit (part no.275-310) that requires 1.2 volts DC to activate. No current spec was given but I assume it needs just a few __ Designed by Bill Bowden
12V Flourescent Lamp Inverter - Drive a standard 36/40W fluoro tube to fll brightness from a 12V DC. Ideal for camping, a trouble light or even emergency home lighting.__ SiliconChip
12V Fluorescent Inverter - This is a low-cost project for 20 or 40 watt fluorescent tubes. However the most efficient is to use a 40 watt tube (or two 20 watt tubes in series) . It's a circuit you can put together from junk box components or build from a kit. It's very simple to build and requires no printed circuit board __ Contact: Colin Mitchelltalking @ tpg.com.au
12v Light Dimmer V2 - This version controls lights, LEDs and even motors with only 10 componentsup to 50W __ Contact: P. Townshend EduTek Ltd
12v Light/Dark Lamp Switch - At night, this circuit will route current to a 12v lamp, turning it on. . . Circuit by David Johnson P.E.-July, 2006
12V Speed Controller/Lamp Dimmer - This handy circuit can be used as a speed controller for a 12V motor rated up to 5A (continuous) or as a dimmer for a 12V halogen or standard incandescent lamp rated up to 50W. It varies the power to the load (motor or lamp) using pulse width modulation (PWM) at a pulse frequency of around 220Hz.__ SiliconChip
12v Touch Switch Exciter Circuit - This circuit is designed to generate a 20KHz pseudo sine wave signal that can power about 50 remote touch activated switch circuits. It can support a cable length of about 2500 feet. A typical remote switch circuit is also shown as well as a receiver circuit for those switches.. . . Circuit by David Johnson P.E.-February, 2002
12VDC Fluorescent Lamp Driver - This fluorescent lamp driver uses a normal 120 to 6V step-down transformer in reverse to step12V to about350-Volt to drive a lamp without need to warm filaments. __ Designed by Aaron Cake
14 Volt Lamp Dimmer (using a pot) - Here is a 12 volt / 2 amp lamp dimmer that can be used to dim a standard 25 watt automobile brake or backup bulb by controlling the duty cycle of a astable 555 timer oscillator. When the wiper of the potentiometer is at the uppermost position, the capacitor will charge quickly through both 1K resistor __ Designed by Bill Bowden
14v LED AuxiliaryLamp with a 60 Watt Lamp - This circuit controls power to a standard 60 watt lamp plus generates an auxiliary 14v DC supply which can power an automotive style 12 LED array . . . Hobby Circuit designed by David Johnson P.E.-July, 2006
14 Volt Strobe - This circuit uses12V DC instead od mains AC. This is very good idea if you don't want to mess with direct mains voltage connected circuit or you want to run stroboscope from batteries __ Designed by Tomi Engdahl
15–58VIN to 33.3V 3A LED Automotive Headlight Driver with Up to 98.5% Efficiency - Airplanes and big trucks with 24V batteries need powerful, efficient and robust headlights and spotlights. This circuit shows a 33.3 V, 3A (nine Luminus SSR-90 LEDs) buck-boost LED driver that runs from 15V to 58V input with up to 98.5% efficiency. The 4-switch synchronous topology drives high power LEDs with minimal switch power loss (and minimal temperature rise) __ Linear Technology/Analog Devices App Note, Mar 9th 2012
16 Stage Bidirectional LED Sequencer - The bi-directional sequencer uses a 4 bit binary up/down counter (CD4516) and two "1 of 8 line decoders" (74HC138 or 74HCT138) to generate the popular "Night Rider" display. A Schmitt Trigger oscillator provides the clock signal for the counter and the rate can be adjusted with the 500K pot. Two additional Schmitt Trigger inverters are used as a SET/RESET latch to control the counting direction (up or down) . Be sure to use the 74HC14 and not the 74HCT14, the 74HCT14 may not work due to the low TTL input trigger level. When the highest count is reached (1111) the low output __ Designed by Bill Bowden
18 LED dimmable LED lamp - This circuit is a dimmable white LED lamp array with 18 LEDs. The lamp brightness is regulated as long as the input voltage is above 10.5V. A low-dropout analog voltage regulator is used for a simple and relatively efficient __ Designed by G. Forrest Cook
18 Stage LED Sequencer - The question sometimes comes up of how to cascade 4017 decade counters for more than 10 sequencial stages. The LED sequencer above shows a possible solution using a few extra parts. When power is applied, the 15K resistor and 10uF cap at pin 15 will reset the counters to the zero count where pin 3 is at +12 and all other outputs are at zero. The 2 diodes (1n914) and 15 resistor form a AND gate so the clock pulse will be passed to the right side counter when the sequence starts. When the right counter reaches the 10th count, . __ Designed by Bill Bowden
1W White LED Night Light - As many of you know, I have a pet peeve with poorly made LED night lights. Often, the light from the LED quickly fades, so within months, the light is useless. I have posted several versions of modified night lights using higher quality components. This circuit is yet another version, which produces much more light than those other designs. . . . Hobby Circuit designed by Dave Johnson P.E.-November, 2008 |
