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Last Updated: December 01, 2017 03:41 AM

Circuits Designed by Dave Johnson, P.E.

Fluorescent Lamp Intensity ModulatorThis hobby circuit was designed to experiment with using small fluorescent lamps as a broad pattern source of modulated light.  This hobby circuit hits the small lamp with narrow 1us pulses at a rate of 10KHz.  Each pulse launches about 10 watts of visible light.  The lamp starting method is a bit crude but the circuit does work. . . . Hobby Circuit designed by David A. Johnson P.E.-June, 2000

Fluorescent Lamp Night Light Needs Only 1 WattIf you are tired of replacing small night light lamps, try this circuit.  The line powered circuit uses a long life cold cathode fluorescent lamp.  A simple charge pump technique runs the lamp without any transformer . . . Hobby Circuit designed by Dave Johnson P.E.-March, 1999




Links to electronic circuits, electronic schematics, designs for engineers, hobbyists, students & inventors:

Flashing LED with PIC12F629 -  This is the first example that you should to know how to set output pin.  In this example, GPO is set as an output.  LED1 will be turn-on when GP0 is set high and LED1 wiil be turn-off when GP0 is set low.  This example use 4MHz internal clock.  

Flashing LED-Based Solar Engine -  Voltage-Controlled Solar Engine:This design uses a flashing LED to determine the solar engine's voltage trip level.   __ Designed by Wilf Rigter

Flashing light / emergency beacon for vehicle -  No circuit description, schematic only__ CdS Electronic

Flashing Lights for Planes & Helicopters -  NOTE : Must register on this site __ Designed by Published in Elecktor July/Aug, 2010

Flashing Neon Christmas Lights -  One of the bummers of Christmas is trying to get the strings of lights to work.  The biggest culprit are the strings that are connected in series.  These are usually the strings of so-called miniature Christmas lights with the push-in bulbs.  You've probably read on the box that when one light goes out the rest stay lit.  True, the light bulbs have an internal "shunting device" so that if one burns out, it doesn't break the circuit and the rest of the lights do stay lit.  But the problem is that if the circuit should become broken at any other point, the whole string goes out.  The usual place this happens is between the lamp and the socket, especially if the string is used outdoors.  This is because water in the socket causes the thin copper lamp wires to oxidize, which prevents them from conducting electricity.   Sometimes the wires on the lamp can become completely eaten away.  At any rate, it breaks the circuit and the string doesn't work. __ Designed by Colin Pringle   colin @ wild-bohemian.com

Flashing Neons (NE-51 / NE-2) -  In this circuit, one, two or three neon indicator bulbs can be made to flash in sequence at rates determined by the R and C values.  In the single stage circuit, using one lamp, the capacitor charges through the resistor until the ionization potential of the neon is reached (about 70 volts) and __ Designed by Bill Bowden

Flashing Railroad Lights -  This circuit flashes two red LEDs for a model railway crossing.  __ 555-Timer

Flashing Red LED Light-1970's Style Caboose Marker -  A circuit that drives a red LED from a 1.5 volt battery and simulates an incandescent light.  Duty cycle can be changed by selecting resistor values __ Designed by Dick Cappels

Flashing/Pulsing third Brake lite for cars -  Several years ago these flashers were introduced in the automotive industry as part of the third brake light and contained strobe lights   (and strobing continuously for the duration of pressing the break pedal) but got abandoned almost immediately sometime later because of the 'strobe' effect it has on some people.  This circuit has become obsolet since much better circuits are available these days without the 'lag' in between brakes caused by R4 and C3.  One of the circuits is listed below __ Designed by Tony van Roon  VA3AVR

Flashing-Cum-Running Light -  This circuit generates flashing lights in running pattern.  In conventional running lights, the LEDs glow one by one.  In this circuit, the LEDs flash a number of times one by one.The...__ Electronics Projects for You

Flashing-LED Battery-status Indicator -  Signals when an on-circuit battery is exhausted; 5V to 12V operating voltage __ Contact: Flavio Dellepiane, fladello @ tin.it

Fleapower Flasher Draws Less Than 50 µA -  01/23/03 EDN-Design Ideas Frequency source feeds entire labSome applications require a circuit to indicate that a battery's voltage has fallen below a certain value.  However, if you don't frequently check the indicator, the low-battery indicator itself can easily discharge the battery.  The circuit in Figure 1 indicates when the battery voltage has dropped below a preset value __ Circuit Design by Gary Butterfield, IEC Electronics Technology Center, Newark, NY

FLED-basedType 1 (Voltage Controlled) Solar Engine -  This design uses a flashing LED to determine the solar engine's voltage trip level. __ Designed by Wilf Rigter

Flicker Lamp -  Having bought a cute little ‘paraffin lamp’ from a cut price shop, I decided to make it a little more interesting.  Its battery powered of course but its continuous shine and simple on / off ‘wick control’ did not make for anything like a close simulation of the real thing.  So, I replaced the on / off control with a variable potentiometer and I added flicker! __ Contact: Karen's Microprocessor Projects

Flickering Fire Effect -  This simple circuit uses four low-Wattage colored bulbs and four fluorescent lamp starters to make nice flickering flame effect

Flickering Lights -  Halloween flickering lights __ Designed by Wolf Stone

Flip Flop -  In this project we examine one of the most valuable circuits to be invented, the flip flop.  Originally it was designed with VALVES, along with its simpler version (without the two capacitors, called a bi-stable Multivibrator) , it was realised it  __ Contact: Colin Mitchelltalking @ tpg.com.au

Flip Flop Flashers Buzzers Etc -  Several circuits here.  The familiar astable flip-flop circuit is a handy configuration for making flashers or generating squarewaves.  Here is a typical alternating LED flasher with the LEDs in the emitters instead of collectors as is normally done.  The bias resistors are directly connected __ Contact: Charles Wenzel of Wenzel Associates, Inc.

Floating Surge Stopper Provides Unlimited Overvoltage Protection -  Protecting sensitive electronic circuitry from voltage transients is an essential part of any system be it automotive, industrial, avionics or even battery-powered consumer applications.  offers a wide variety of solutions for these applications with its surge stopper family.  The LTC®4366 is the new exciting __ Linear Technology/Analog Devices App Note, Hamza Afzal Applications Engineer-Mixed Signal Products Nov 7th 2012

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 __ Designed by Collin Mitchell

Fluorescent Lamp Driver-12VDC  -  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

Fluorescent Lamp Intensity Modulator -  This hobby circuit was designed to experiment with using small fluorescent lamps as a broad pattern source of modulated light.  This hobby circuit hits the small lamp with narrow 1us pulses at a rate of 10KHz.  Each pulse launches about 10 watts of visible light.  The lamp starting method is a bit crude but the circuit does work. . . . Hobby Circuit designed by David A. Johnson P.E.-June, 2000

Fluorescent Lamp Inverter -  This inverter is very easy to construct, reliable, and even powerful enough to light up a 15W florescent tube (if you cool your transistor well).  The only hard-to-find piece of this baby is the so-called yellow inverter transformer.  It's a miniature high frequency transformer that has a 25mm x 20mm x 5mm ferrite core, 30 turns of primary, 15 turns of feedback, and 250 turns of secondary all concentric, wound on plastic frame than wrapped with a 'yellow' adhesive tape.  If you can't find it in your local electronic shops then search for old portable rechargeble florescent lanterns since they have at least one yellow inverter.  Of course you can wind a handmade transformer which would do the same but it is a very difficult task when you don't have an original to inspire and it will still need an appropriate ferrite core.  

Fluorescent Lamp Night Light Needs Only 1 Watt -  If you are tired of replacing small night light lamps, try this circuit.  The line powered circuit uses a long life cold cathode fluorescent lamp.  A simple charge pump technique runs the lamp without any transformer . . . Hobby Circuit designed by Dave Johnson P.E.-March, 1999

Fluorescent Light -  How to build a 4-Watts Fluorescent light using a disposable camera, powered by one 1.5 Volts battery.   __ Designed by Jose Pino

FM RDS Tuner Module -  Stereo FM band receiver with RDS decoding for mobile applications.
Continuous full RDS data output through RS232: RDS PS, PI, TA/TP/TMC, CT, TMC.  Full Radio Text supported: 2x64 characters.  Raw TMC data output. __ Designed by Michel Bavin

FM RDS/RBDS + AM tuner Module -  High quality integrated tuner module for worldwide FM, RDS/RBDS and AM reception.  Receives full FM, LW, MW, and SW bands.   __ Designed by Michel Bavin

FM Transmitter -  While there are a plethora of similar 2-transistor schematics available, this one is above average.  A major improvement overlittle 1-transistor circuit that we've discussed previously, this transmitter consist of two stages.  first transistor is used to amplify audio, 

FM Transmitter Circuit -  Schematic only, no circuit description is included __ Designed by Kamran Ahmed-UK

Fogger Smoke Machine -  Foggers used to generate fog and smoke effects operate by heating a special fogger fluid.  They consist of a heting element which is kept in the right temperature using a thermostat.  When the operator want to generate smoke, he/she presses the controller button which starts the pump which pumps fog fluid to the heating element.  When smoke fluid enters the heating element, in starts to evaporate and produce smoke.   __ Designed by Tomi Engdahl

Force/sense connection eliminates multiplexer on-resistance error -  22-Jan-04 EDN-Design Ideas Digitally controlled gain is an everyday analog-design element.  You frequently find this element in an op-amp-based, transimpedance current-to-voltage converter.  When you design digital gain control into such a converter, the usual scheme is to arrange things such that a digital multiplexer selects the appropriate feedback resistor for each gain figure __ Circuit Design by Stephen Woodward, Marine Sciences, Chapel Hill, NC

Form Fast, Portable Light Pulser -  10/16/03  EDN-Design Ideas The absence of a fast one-shot multivibrator in the entire TTL family, as well as the low-voltage swing and unwieldy supply requirements of ECL, drove us to exploit the fast transition times and low propagation delays of F-series g __ Circuit Design by SK Kaul and IK Kaul, Bhabha Atomic Research Centre, Trombay, Mumbai, India

Four Channel CAR Color Organ -  Back in the 1970's these were popular for use in homes and the colored bulbs were typically place in a box with a sheet of "rippled/bubbled" Plastic in front to break up the light patterns.  Some units gave very impressive light patterns.   __ Designed by G.L. Chemelec

Four Channel Dimmer Rack -  Note: This document describes my light dimmer project I have made.  This document is not ment to be a full construction project and it might lack some details.  The document is designed as an example those who might think to design and build their own dimmer circuit.  If you are plannign to take such project then I must warn you that you must know quite a bit of safetu issues before even thinking of building this kind of device which is connected directly to mains and controls lots of power (mistakes might mean electrical safety and fire safety dangers).   __ Designed by Tomi Engdahl

Four Channel HOME Color Organ -  FOUR Channels.  All Channels are Active Band Pass Filters.   __ Designed by G.L. Chemelec

Four Channel PWM Controller. Part 1 -  Pulse width modulation (PWM) is a useful control technique for such applications as light dimming and motor speed control. The aim of this project was to design a low cost PWM controller that would be useful in many areas where PWM is employed. __ Designed by Radio LocMan

Four Channel PWM Controller-Part 2 -  All of the ATMega32 software was written in assembler within the AVR Studio IDE environment. This has allowed easy simulation and debugging of the code, and quick transfer of the latest software version to the board via the AVRISP programmer. __ Designed by Radio LocMan

Four-Channel Remote Control -  You can construct your own long range infrared (IR) wireless remote using Motorola's MC145026 emitter and MC145027 detector chips.  With your remote you can control devices up to 20 feet (7 meters) away.  It operates similiarly to a TV remote.  You just point the emitter at the detector, push a transmit button.  The detector then interprets your data signal.  You can use this circuit to remotely turn on/off devices (like a motors, relays, home appliances).   __ Designed by Boondog web site

Four-Digit Keypad Controlled Switch -  Universal Keypad-Controlled Switches:  This is a Universal version of the Four-Digit Alarm Control Keypad.  I have modified the design to free up the relay contacts.  This allows the circuit to operate as a general-purpose switch.  I've used a SPCO/SPDT relaybut you can use a multi-pole relay if you wish.  __ Designed by Ron J.

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Control Circuits:   #'s - A       B - C       D - G        H - L       M - P        Q - S        T - U        V - Z


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