Telephone FM Transmitter - This FM transmitter attaches in series to one of your phone lines. When there is a signal on the line (that is, when you pick up the handset) the circuit will transmit the conversation. In particular it will radiate from the phone line itself. It is a passive device, there is __ Designed by Electronics DIY
Ten 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
Ten-Channel Light Controller - A 10 channel light controller using PWM/ up to 1a per channel at 12v __ Contact: P. Townshend EduTek Ltd
Ten-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 Ten-LED Sequencer - Schematic only, text in Finnish
Ten-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 A. Johnson P.E.-April, 2011
Tester Checks Christmas-Tree Lights - 12/23/99 EDN-Design Ideas Why is it that you always test 48 bulbs before you find the bad one in a 50-light string? This simple circuit allows you to divide and conquer, greatly reducing the time it takes to find the bad bulb. Design by William Dias, Brown & Sharpe, North Kingstown, RI
The Inexpensive Dimmable LED Desk Lamp - 30-Nov-12 -Design News: Andrew Morris designed a dimmable LED driver circuit that is simple and energy efficient. He then installed the circuit into a portable fluorescent lamp. __ Designed by Andrew R. Morris, Gadget Freak-Case #230
The LED Flasher - This is a very simple project using a printed circuit board and 8 components. It will flash an ordinary 3mm or 5mm (1/8" or 1/4") LED at a rate of about one flash per second. __ Designed by Collin Mitchell
The LED Flashing Sweetheart Kit - When was the last time you gave a gift you made yourself? Elementary school? Get off the consumerist fast track and quit copping out with inferior gifts like candy and flowers. The LED Flashing Sweetheart Kit contains a circuit board, 28 LEDs
The Lights Are On, but No One's Home - Find out how you can control your environment. __ Contact: Jameco Electronics
Third Brake Light - This circuit is NOT a pulser or flasher! What's so special about this circuit? Well, the first third-brake light I installed I had to pull a wire from the Third Brake Light all the way underneath the carpet to the brake-pedal-switch and I thought it would be easier to pluck the signal of both brakelights via the trunk. Bench-test your circuit first and apply power to the circuit, __ Designed by Tonny Von Roon
Third Brake Light Pulser - 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
Three Channel Color Organ for a Car - An Active Filter Design. __ Designed by G.L. Chemelec
Three Channel Color Organ for a Car - An Active Filter Design. __ Designed by G.L. Chemelec
Three Volt Universal LED Flasher - The circuit below will flash any LED color with fixed current pulses powered by a 3v battery. It uses a charge pump approach, which routes a constant current pulse through the LED, regardless of the LED voltage requirement. Using this approach, white and . . . Hobby Circuit designed by David Johnson P.E.-June, 2008
Three-Minute Closet Light - I have a coat closet by my front door. The thing is very dark at night and really needs some kind of illumination inside. I could hire an electrician to install a light in the closet ceiling and then wire it to a toggle switch outside the door but that would cost me quite a bit of money. . . Circuit by David A. Johnson P.E.-December, 2011
Three-Volt Low Battery Voltage Flasher - Many battery powered devices use two AA alkaline cells. Often you will not know when it is time to replace the batteries until the device powered by them actually stops operating. The hobby circuit below can be connected to a 3v battery, to give you some . . . Hobby Circuit designed by David Johnson P.E.-January, 1998
Three-Volt Powered Super Bright LED Flasher - I have posted several kinds of LED flashers over the years. This is yet one more flasher, designed to flash any high power LED of any color. It hits the LED with a 25ms 250ma pulse once every 2 seconds. This works out to an average current about 3ma. It . . . Hobby Circuit designed by David Johnson P.E.-April, 2009
Time Delay Relay-Power OFF - The two circuits below illustrate opening a relay contact a short time after the ignition or ligh switch is turned off. The capacitor is charged and the relay is closed when the voltage at the diode anode rises to +12 volts. The circuit on the left is a common collector or emitter follower and has the advantage of one less part since a resistor is not needed in series with the transistor base. However the voltage across the relay coil will be two diode drops less than the supply voltage, or about 11 volts for a 12.5 volt input. __ Designed by Bill Bowden
Time Delay Relay-Power ON - Here's a power-on time delay relay circuit that takes advantage of the emitter/base breakdown voltage of an ordinary bi-polar transistor. The reverse connected emitter/base junction of a 2N3904 transistor is used as an 8 volt zener diode which creates a higher turn-on voltage for the Darlington connected transistor pair. Most any bi-polar transistor may be used, but the zener voltage will vary from about 6 to 9 volts depending on the particular transistor used. Time delay is roughly 7 seconds using a 47K resistor and 100uF capacitor and can be reduced by reducing the R or C values. __ Designed by Bill Bowden
Timer Exploits OpAmp Bias Current - 07/21/94 EDN-Design Ideas The simple, low-cost analog timer in Fig 1 exploits the parasitic input-bias current of op-amp IC1. The timer achieves long time delays even though it uses only low-value, inexpensive ceramic chip capacitors. After all, because the input-bias current is the minimum current flow into an op amp, Design by Aleksandr Belousov, Baltimore, MD
Touch Activated Lamp - The circuits below light a 20 watt lamp when the contacts are touched and the skin resistance is about 2 Megs or less. The circuit on the left uses a power MOSFET which turns on when the voltage between the source and gate is around 6 volts. The gate of the MOSFET draws no current so the voltage __ Designed by Bill Bowden
Touch Activated Switch - This circuit provides about one watt of non-isolated DC power for an automotive type 12v LED array lamp in addition to a standard incandescent table lamp.. . . Circuit by David A. Johnson P.E.-January, 2002
Touch and/or Remote Controlled Light Dimmer - Old-fashioned light dimmers with knobs are passe! This one dims up or down at a touch or you can use an infared remote control.__ SiliconChip
Touch dimmer switch - By simply touching this touch dimmer switch you can increase the light intensity of incandescent lamps in three steps. Initially, when mains switch is on, the bulb is off. Now, if you touch the touch plate, the bulb glows dimly. On second touch, __ Designed by Radio LocMan
Touch and/or Remote Controlled Light Dimmer-Part 2 - Completing the construction and building the touchplate and pushbutton dimmer extensions.__ SiliconChip
Traffic Light - A two-way traffic light using a CMOS
4017 and 555. To be used as toy only __ Designed by Jose Pino
Traffic Light - This project operates red, amber and green LEDs in the correct sequence for a single UK traffic light. The time taken for the complete red, red & amber, green, amber sequence can be varied from about 7s to about 2½ minutes. A 4017 counter is used to produce the traffic light sequence and this project could be adapted __ Designed by John Hewes
Traffic Light 2 -
A two-way Traffic light using a PIC 12F629. As bonus, a traffic
light that doesn't use a PIC is included. (05/13/2004). __ Designed by Jose Pino
Touch Dimmer - By simply touching this touch dimmer you can increase the light intensity of incandescent lamps in three steps. The touch dimmer is built around 8-pin CMOS
IC TT8486A/TT6061A specifically manufactured for...__ Electronics Projects for You
Traffic Light Controller - Controls on3 LED traffic light sequence __ Designed by rstevew@armory.com
Traffic light controller using an Arduino microcontroller - The Traffic Light Hack is a simple interface for controlling lights inside a traffic light enclosure. No, not a real light out on the street. This one was picked up at a flea market, and it's hanging in my room. __ Designed by Rockwell Schrock
Transistor Flasher - The basic two-transistor flasher shown below has found its way into dozens of applications due to its simplicity and versatility. Applications have included such diverse circuits as a micropower low battery indicator, a lightning detector, . __ Contact: Charles Wenzel of Wenzel Associates, Inc.
Transistor LED Flasher - A simple LED flasher that uses only two transistors, one capacitor and one resistor. This basic oscillator can have other simple applications. __ Designed by Jose Pino
Transistor LED flasher - This circuit has a lot going for it. For one thing, it only consists of two transistors, two capacitors and four resistors. That also means it consumes very little power. You can control the flash rate by changing the size of the 100k resistors (100k makes for a pretty slow rate) . You can also control the duty cycle by using resistors of different values on the two sides __ Designed by Colin Pringle
Transistor Organ - This simple circuit can provide hours of enjoyment as you learn tunes, play duets or just make some really weird sounds by pushing all the buttons at once. You have probably seen this circuit before, it is fairly common. I have seen it in several __ Designed by Aaron Cake
Transmitter for Line Powered Xenon Flash - This line powered xenon flash circuit drives a small camera type flash tube. It has an optical isolator to allow the flash to be safely triggered from some remote device. A flash rate of 2Hz is possible with the circuit . . . Hobby Circuit designed by Dave Johnson P.E.-June, 2000 |