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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.... [Bill Bowden's
website] |
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18 LED dimmable LED lamp - bright LED cluster [G. Forrest Cook] |
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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,.. [Bill Bowden's
circuit] |
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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. The circuit brings together
two high power white LEDs made by Cree with a compact AC to DC power supply from Bias
Power..... [Designed by David A. Johnson] |
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2 Transistor LED Flasher - This 1.5 volt led fasher runs more than a year on
a single 'd" cell and alternately flashes 2 LEDs at about a 1 second rate. The circuit
employs a 74HC14 CMOS hex inverter that will operate at very low voltages (less than 1
volt). One section is used as a squarewave oscillator (pins 1 and 2), while the others
are wired to produce a short 10mS pulse on alternate edges of the square wave so the
LEDs will alternate back and forth. The output sections each use a capacitor charge
pump to increase the voltage for the LEDs..... [Bill Bowden design this one] |
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2 Wire DC Lamp Dimmer replaces Rheostats - 10/23/97 EDN-Design
Ideas.....Originally for use in commercial trucks, a low-cost dc lamp dimmer (Figure
1]can control more than 100W of incandescent panel lighting and replaces a high-power
rheostat, whose heating darkens instrument panel.… [Design Idea by Kevan
O'Meara, KO Systems, Chatsworth, CA] |
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2 Wire Lamp Flasher - Ideal to operate3 to24 Volt DC existing on-Circuit
lamps LED operation is also possible (added 6/06) |
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Ballast - I use this circuit for general
use to power white LEDs, like a headset light I use on my desk and a keyboard light
for my computer. I built it into a tiny Radio Shack project box (270-288), which they
no longer sell. I put heat-shrink tubing around the female output connector (RS P/N
273-1743), so that the contacts are not exposed, but you can still plug and unplug
it.....[Designed by Andrew R. Morris (added 9/05)] |
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220 Volt Flashing Lamps - This circuit is intended as a reliable replacement
to thermally-activated switches used for Christmas tree lamp-flashing. The device
formed by Q1, Q2 and related resistors triggers the SCR. Timing is provided by R1,R2 &
C1. To change flashing frequency don't modify R1 and R2 values: set C1 value from 100
to 2200µF instead.…..... |
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220 Volts Flashing Lamps - Especially designed for Christmas tree lamps.
Replaces old thermally-activated switches. (electronic circuit added 06/07/08)
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220V Flashing lights - This circuit is intended as a reliable replacement to
thermally-activated switches used for Christmas tree lamp-flashing. The device formed
by Q1, Q2 and related resistors triggers the SCR. Timing is provided by R1,R2 & C1. To
change flashing frequency don't modify R1 and R2 values: set C1 value from 100 to
2200΅F instead.... |
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230V Blinking LED - This design can be of some interest for those wanting
striking light signs, as it can drive up to three 230V lamp strings in three operating
modes. The 15V dc supply is obtained from a nominal 230/24V center tapped ac
transformer (T1) and a full wave rectifier.....(electronic design added 09/08)
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230V Dimmer - A reliable and efficient all-around performer. I bought
kit because it didn't cost me much more than components were worth and I also
got a nice professional-made PCB inside. As you can see, this is a tried-and-true diac
& triac combination that offers both simplicity and high performance. With a load up
to 3.5A, power rating is 750W at 230V. A heat sink on triac is a
must!.....(added 11/05) |
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25 Light Sequencer using Xmas Lamps - This circuit above can drive 25 small
Xmas lights. The lights operate at about 200mA and 3 volts. The supply voltage is set
to 5 volts and the 4017 counter output will drop about a volt using the 2N3053
transistors. The voltage on the emitters of the rows transistors will be about 0.7
volts less than the base so the lamp voltage will be about 3 volts. You can..... [Bill
Bowden] |
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250ksps 16-Bit Micropower ADC offers an Excellent Combination of Size Power & Speed
- DN294 Design Notes (Linear Technology) (app note added 6/06)
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2-wire Lamp Flasher - This circuit has been designed to provide that
continuous light lamps already wired into a circuit, become flashing. Simply insert
circuit between existing lamp and negative supply. Especially suited for car or panel
pilot lights, this device can drive lamps up to 10W(design added 11/06) |
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