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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. |
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12F675 as a Flip Flop - Code to make a 12F675
operate as a D-type or JK-type flip flop. Since I
implemented a D type flip flop using PIC Logic
Elements I thought I might go or way and implement
an entire D type flip flop in a single PIC. This
uses edge triggered and port change status
interrupts and was an opportunity to have a play
with interrupts on PIC. |
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3v Capacitance Proximity Switch - This circuit
was designed to provide a touch activated switch
function without an external power supply. It draws
so little power that a single 3v battery will
operate the circuit for many years. It is discussed
in more detail in the section on Capacitance
Proximity Switch Technology. (Note: link is
off-site) |
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555 Bistable Circuit - Basic circuits and
information about this timer/oscillator. Scroll to
find Bistable Circuit |
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An SCR Flipflop for Alternating Flashing Light
Bulbs |
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AN-1150: COP8 FLASH ISP HANDBOOK-Intro to ISP -
National Semiconductor Application Note |
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AN-1281:Bumped Die Flip Chip Packages - National
Semiconductor Application Note |
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CMOS Toggle Flip Flop using Laser Pointer - The
circuit below uses a CMOS dual D flip flop (CD4013)
to toggle a relay or other load with a momentary
push button. Several push buttons can be wired in
parallel to control the relay from multiple
locations. A high level from the push button is
coupled to the set line through a small (0.1uF)
capacitor. The high level from the Q output is
inverted by the upper transistor and supplies a low
reset level to the reset line for about 400 mS,
after which time the reset line returns to a high
state and resets the flip flop. |
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CMOS Toggle Flip Flop Using Push Button - The
circuit below uses a CMOS dual D flip flop (CD4013)
to toggle a relay or other load with a momentary
push button. Several push buttons can be wired in
parallel to control the relay from multiple.. |
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DAC & flip flops form constant current source -
04/23/09 EDN- Design Ideas, Using two flip flops,
you can program a serial-input DAC to produce a
constant 4 mA.. |
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Descrete Set/Reset Flip Flop - Here are two
examples of bistable flip flops which can be toggled
between states with a single push button. When the
button is pressed, the capacitor connected to the
base of the conducting transistor will charge to a
slightly higher voltage. When the button is
released, the same capacitor will discharge back to
the previous voltage causing the transistor to turn
off. The rising voltage at the collector of the
transistor that is turning off causes the opposite
transistor to turn on and the circuit remains in a
stable state until.. |
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D-Flip/Flop One Shot Circuit - Yes you can use
cheap D flip/flop logic circuits as nice one-shot
pulse generators. This schematic shows how the
popular CD4013 and the CD74HC74 can be used to
generate pulses ranging from nanoseconds to seconds. |
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D-Flip/Flop Oscillators - Yes you can turn
flip/flop ICs into low current oscillators. This
schematic shows you how. |
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Discrete BiStable Flip Flop |
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Discrete Set/Reset Flip Flop - This is an
example of a set/reset flip flop using discrete
components. When power is applied, only one of the
transistors will conduct causing the other to remain
off. The conducting transistor can be turned off by
grounding it's base through the push button which
causes the collector voltage to rise and turn on the
opposite transistor. |
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Dual flip flop forms simple delayed pulse generator
- EDN-Design Ideas: A delayed pulse generator
provides precision timing adjustments.. |
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Electronic circuit replaces mechanical push push
switch - EDN-Design Ideas: Toggle-action circuit
uses a low-cost momentary-contact switch.. |
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Flashing LED Advertising Badge #1 - I have seen
numerous flashing light badges at trade shows and
conventions. They are often handed out as gifts to
promote some business. The devices often use
inefficient circuits, which cause the battery power
source to be quickly depleted. My circuit is simple
but efficient enough to provide months of continuous
LED flashing. It also has a tiny push-button switch
to turn on and off the light flashing, extending
battery power. |
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Flashing LED Advertising Badge #2 - This circuit
is similar to flashing LED advertising badge #1. .
It uses a CD4013 dual D Flip/Flop IC. The 74HCT74
IC in #81 does not always work. As in #81, a single
lithium battery will provide months of continuous
LED flashing. It also has a tiny push-button switch
to turn on and off the light flashing. |
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Flip Flop Circuit - 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. |
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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.. |
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Follow the Debouncing Flip Flops - EDN-Design
Ideas |
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FPGA Circuit Emulates 74x74 Flip Flop - EDN-Design
Ideas |
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FPGA implements X.50 Division 3 recommendation -
EDN-Design Ideas: The scheme in Figure 1a uses five
delay cells and an XOR gate to configure the data
stream for the X.50 Division 3 recommendation of ITU-T.
The X.50 recommendation defines the fundamental
parameters of a multiplexing scheme for inter
working data |
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Gated Oscillator Emulates a Flip Flop - EDN-Design
Ideas |
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High Current MOSFET Flip Flop with Debounced
Pushbutton - This circuit was adapted from the
"Toggle Switch Debounced Pushbutton" by John
Lundgren. It is particularly useful in controlling a
load from several locations where the load may be
switched on from one location and switched off from
another. Any number of momentary (N/O) switches or
push buttons may be connected in parallel.
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Honeybee Counter - I designed a circuit similar
to this one a long time ago to help a beekeeper
count the number of bees going into or out of a
hive. The low power circuit uses a slotted opto-sensor
to detect the passing bees. The circuit advances an
electronic counting module whenever a honeybee
passes through the sensor. The device only counts
the number of bees going through the sensor. A
different circuit would be needed to count the
number of bees only going out or only coming into
the hive. |
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Miniature Pushbutton On/Off Switch - In many
battery powered devices, you would like to turn the
circuit on and off by pressing a small pushbutton
switch. One press turns the device on and second
press turns it back off. The flip/flop circuit
below uses a minimum number of parts to perform this
function. It operates from DC supply voltage which
can range from 2v to 6v. It draws very little
current and takes up little space. Yet, it can
control up to one amp of current. The circuit uses
a single flip/flop device made by Texas
Instruments. |
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Monostable Flip Flops One Shot |
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On/Off Flip/Flop Circuit With Automatic Timeout
- This circuit is ideal when a device needs to be
turned on and off with a single pushbutton switch,
but also needs to turn itself off after some period
of time. With the components shown, the output will
stay on for only about 20 seconds. |
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Pushbutton Oneshot & Latch - This circuit uses a
single IC to convert a noisy pushbutton switch
signal into a clean pulse or a sustained push
on-push off signal. It can operate from 3v to 18v. |
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SCR Flipflop for Alternating Flashing Light Bulbs |
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Set/Reset Flip Flop |
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Soft On/Off Switch -
This project describes how to build a "soft touch"
switch. By "soft touch" we mean that you have to
push once to set device ON and push again to set
device OFF. This kind of switch works by latching a
relay to ON state with push of a button and with
another push latch is released. It is working like
flip-flop states. In that way you can control power
to a device using one push button |
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Sound Controlled Flip Flop - Described here is a
very inexpensive solution to many phono-controlled
applications like remote switching on, for instance,
or activating a camera, tape recorder, burglar
alarms, toys, etc. The circuit given here employs a
condenser microphone as the pick-up. A two-stage
amplifier built around a quad op-amp IC LM324 offers
a good gain to enable sound pick-up upto four
metres. |
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Spare flip flop stretches WR strobe for DSP -
EDN-Design Ideas |
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Spare gates form edge triggered flip flop - EDN-Design
Ideas |
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Telephone Line Based Audio Muting & Light on Circuit |
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Telephone Line Based Audio Muting & Light-On Circuit |
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Time to Dust Indicator - I thought about this
circuit when I heard that a lot cleaning personal in
hotels were either dusting rooms more often than
necessary or not enough. I have not yet built and
tested this circuit completely but in concept it
should work. The circuit draws very low current from
a +3v battery and could be housed in a package
similar to a small ashtray. The assembly might be
placed in a suitable out of the way area to collect
dust. It would alert a maid when it was time to dust
the room. The circuit detects dust with an infrared
LED that is pulsed so its light shines onto a smooth
flat plate. Any dust settling onto the surface is
detected by a phototransistor, mounted at a
90-degree angle from the LED. When the dust reaches
a particular level, sufficient light is reflected
into the phototransistor to change the logic state
of the circuit to an alarm condition. The alarm
output could be connected to a beeper, a flashing
LED or to one of the LED flashing circuits in this
hobby circuit section. |
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Verilog Program Models metastable flip flop -
EDN-Design Ideas |
