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�C Provides Wireless Keypad
Control: 10/08/98 EDN-Design
Ideas |
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1.5-V battery-powered fan
switches on and off by hand:
07/26/99 Electronic Design - Ideas for Design /
This circuit represents a very simple and
inexpensive alternative to an electrical switch
used to turn ON and OFF the battery-operated dc
motor typically employed in handheld fans. It
eliminates. . . |
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2 Line Intercom Plus a Telephone
Changeover Switch:
The circuit presented here can be used for
connecting two telephones in parallel and also
as a2-line intercom. FAIR WARNING -- THIS SITE
HAS ANNOYING POP UP ADS. |
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3 Way Touch Lamp:
A three-way switch to control a lamp
(off-dim-bright, etc.) uses an NE555 Timer to
generate a1-second pulse, triggered by ambient
ac fields that are picked up by the human body.
Read also the circuit description.
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4 Bit �P's a / D Converter
Decodes Keypad's Inputs:
10/13/94 EDN-Design Ideas |
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4 Digit Keypad:
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8 x 8 Audio Video Switch: |
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Alternating On / Off Control: |
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Anticipating timer switches
before you push the button:
04/03/03 EDN-Design Ideas / (Editor's note:
This Twilight Zone-worthy circuit will be the
subject of an upcoming network sitcom, My Big
Fat Anticipating Timer.) It happens to almost
everyone that an apparatus or system should have
been turned off a moment ago. The device in
question could be the car heater, the air
conditioner, the lights |
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Audio Auto Shutoff:
purpose of this circuit is to automatically turn
off any device plugged into its power outlets
after a certain period of Time of silence
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Audio Video Switch:
This is an 8-input x-output audio/video switch
module to be controlled from a computer, for
example from the parallel port. Each audio/video
output can be switched to any of the 8 inputs,
separately.1-module drives1-audio/video output
and has a34-pin connector to plug into the
system interface. You can use video OPA-s on
the4051 output instead. Note that you can get
full integrated video multiplexers from Maxim.
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Automatic Headlight Brightness
Switch:
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Automatic Switch Handles RS-232
Or RS-485 Serial Data : 09/20/04 Electronic Design - Design Briefs /
The need arose for a programmable control system
that handles 8-bit data to have both RS-232 and
RS-485 modes. This requirement was satisfied
with a serial communication
controller-transceiver, an octal buffer, and a
two-line port (Rx and Tx for...
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Bipolar Transistor Boosts
Switcher's Current By 12 times:
05/24/01 EDN-Design Ideas / PDF contains
multiple circuits - scroll to find this circuit.
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Build a zero-power switch
supervisor: 04/05/99
Electronic Design - Ideas for Design / A recent
project requirement specified the need for a
special indicator to show whether a security
switch was used during the time the system was
powered off. Because our system has a real-time. |
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Bypass Switch Speeds Up Data
Through Daisy Or JTAG Chain:
02/16/04 Electronic Design - Design Briefs / A
daisy chain consisting of multiple devices can
be quite cumbersome to control, especially when
the only device that needs updating is the last
one in the chain. Each device in the chain must
be written to, resulting in a slow update rate.
It's. . . |
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Capacitance Proximity Alarm: |
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Capacitive Sensor:
Special design for shop-windows animation Useful
for many types of touch controls
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Cell-Phone-Controlled Audio/Video
Mute Switch:
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Cheap Pushbutton Replaces Rotary
Switch: 10/26/00 EDN-Design
Ideas / PDF contains multiple circuits - scroll
to find this circuit |
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Check Digital Or Linear Circuits
With The Flick Of Switch:
03/03/03 Electronic Design - Ideas for Design /
A simple logic probe in concert with a signal
source can be used to check digital as well as
linear circuits. With the flick of a switch, the
probe can inject a test signal or check the
logic state of a digital signal. Comprising just
one CMOS IC... |
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Circuit efficiently switches
bipolar LED:
11/22/2001 EDN - Design Ideas / The circuit in
Figure 1 represents one method to switch a
bipolar, two-color LED using an SPDT mechanical
switch or relay. This circuit wastes power and
does not work properly if the power-supply
voltage is not substantially more than the sum
of the LEDs' forward voltages. The circuit is,
therefore, marginal, to the point of being
unusable, with a 5V supply and a red or green
LED, which... . |
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Clap Switch: |
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Cold Activated Switch:
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Combinational Conjuring Trick:
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Controlling a Light With Two
Switches: a light or
lights can be controlled by more than1-switch
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Couch DropMomentary On / Off
Floor Switch for Microphones:
data sheet with circuit diagram in PDF format,
includes no-pop mute function
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Dark Activated Switch or Porch
Light Switch:
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Dark-activated LED or Lamp
Flasher: Simple
photo-sensitive circuit - 3V battery supply
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DC Motor Reversing Circuit:
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DC Push Button Motor Control
Circuit: |
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Debouncing Networks Make Reliable
Selector: 06/05/97
EDN-Design Ideas |
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Decimal to BCD Convertor:
This circuit will provide an output in Binary
Coded Decimal from any of the input switches.
The input switches may be expanded to 16
switches, providing a Hexadecimal to BCD
conversion. |
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Digital Combination Lock:
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Digital Switching System:
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Doorbell With Counter: |
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Electronic Keypad:
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Electronic Night Light:
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Four Digit Keypad: |
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Fridge Door Alarm:
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Frost Alarm: |
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Garden Light Switch:
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Infra / Radio Remote Control
Transmitter / Receiver: |
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Infra/radio Remote Control
Transmitter/receiver With PIC:
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Infrared Transmitter and Receiver
Schematic Diagrams:
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Inline equations offer hysteresis
switch in PSpice:
08/16/2001 EDN - Design Ideas /
Smooth-transition switches are convenient
devices in many Spice-based simulators. Their
action can greatly ease the convergence process.
Unfortunately, these devices lack inherent
hysteresis, a helpful feature used to build UVLO
(undervoltage-lockout) systems, oscillators, and
other systems. Intusoft's |
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IR Remote Switch:
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Keyboard scanner provides system
supervision: 01/26/98
Electronic Design - Ideas for Design / The
circuit shown scans a numeric keypad while also
generating 16-ms timing interrupts, low-line
resets, and power-fail warnings for a larger
system (see the figure). The core of the circuit
is a versatile. . . |
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Keypad Encoder Commands Tape
Transport: 09/02/96
EDN-Design Ideas |
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LAN Switch Eliminates Redundant
PHY Chip: 03/31/03
Electronic Design - Design Briefs /
Advances in notebook technology create a thirst
for new features and increased functionality,
culminating in greater cost and shrinking space.
One solution to the cost/space issues is to use
a wide-bandwidth analog local-area network (LAN)
switch that. . . |
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LAN/WAN Ethernet Overcurrent And
Overvoltage Protection:
05/01/00 Electronic Design - Ideas for Design /
Local-area networks (LANs) are short-distance
data communication links typically within a
single building or single campus environment. A
LAN doesn't use common carrier circuits (i.e.,
the public switched telephone net work, or PSTN).
By contrast a. . . |
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Laser Transmitter Schematics:
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Light / Dark Detector:
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Light Controlled Switch #2:
output a control signal suitable for relay
depending on the light level |
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Light Operated Switch:
Originally published in Everyday Practical
Electronics, December1995 |
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Lighting Third Brake Light:
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Lightning Activated Camera
Shutter Trigger:
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Load Sensing Automatic Switch:
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Logic offers complementary switch
control: 12/06/2001
EDN - Design Ideas / The complementary-switch
controller in Figure 1 uses a few inverter gates
to provide drive signals for the complementary
switches. Complementary-switch configurations
find widespread use in synchronous-rectification
circuits, charge pumps, full-bridge control
circuits, and other circuits. The circuit in
Figure 1 provides not only a complementary drive
signal but also a deadtime delay ... . |
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Low power keypad consumes only
100 nA: 01/24/2002
EDN - Design Ideas / Often in the use of
products with keypads, one or more keys become
"stuck" or are being pressed. For example, a
cell phone in the bottom of a purse or in a hip
pocket could have one or more of its keys
inadvertently pressed and held down for a
considerable period. Depending on the circuit
design and implementation of the keypad
interface, this condition could cause excess
current to flow,... . |
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Magnetic Proximity Switch:
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Mains Power Switcher: |
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Maximize Battery Life And
Minimize Replacements:
05/13/02 Electronic Design - Ideas for Design /
Designers and consumers want to maximize battery
life in portable and handheld applications—to
avoid discarding batteries that contain useful
life, and to minimize battery replacements.
Small battery-powered devices with wall-adapter
plug-ins. . . |
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MIDI Controlled Switches:
can drive up to128 individual relays, solenoids,
motors, etc. with a MIDI note-on and note-off
messages |
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MOSFET Replaces Switch #1:
01/20/94 EDN-Design Ideas / By using a cheap,
readily available MOSFET, you can use a
single-pole switch to turn a bipolar power
supply on and off without consuming extra power.
In Fig1, the switch simply controls the MOSFET
gate, which switches on the negative supply.
Resistor R, which can be several megohms, is not
necessary if the �6V rails are permanently
connected to a load, such as an op-amp circuit.
Because the MOSFETs RDS (ON) is a fraction of an
ohm, power loss is minimal, and the circuit
suits moderate-consumption, battery-operated
circuitry |
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MOSFET Replaces Switch #2:
02/03/94 EDN-Design Ideas / You can use a
single-pole switch to turn a bipolar power
supply on and off without consuming extra power
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MOSFET switch provides efficient
AC / DC conversion:
02/17/00 EDN-Design Ideas |
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Multiple Remote Points Control On
/ Off Switch:
06/22/00 EDN-Design Ideas / PDF contains
multiple circuits - scroll to find the one of
interest / |
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One Pin Keypad Features Low
Component Count:
05/26/03 Electronic Design - Ideas for Design /
While current-shunt-monitor ICs like the INA168
can be connected to current-shunt resistors at
supply voltages of up to 60 V, the circuit shown
in the figure allows current sensing at even
higher voltages.... |
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Pine Racecar Victory Judge:
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Ping-Pong Configuration Increases
System's Conversion Throughput:
10/30/00 Electronic Design - Ideas for Design
/Traditionally, "ping-pong" configurations have
been used with sample-and-hold circuits to
increase throughput rates in data-acquisition
systems. To increase throughput, this same
technique can be implemented with standard
analog-to-digital. . . |
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Pushbutton Switch Debouncer: |
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Quickly discharge power supply
capacitors:
07/05/2001 EDN - Design Ideas / A perennial
challenge in power-supply design is the safe and
speedy discharge, or "dump," at turn-off of the
large amount of energy stored in the
postrectification filter capacitors. This
energy, CV 2 /2, can usually reach tens of
joules. If you let the capacitors
self-discharge, dangerous voltages can persist
on unloaded electrolytic filter capacitors for
hours or even days.. |
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:
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: 06/05/96
EDN-Design Ideas |
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: |
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: 12/04/97 EDN-Design
Ideas |
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S Video Source Selector:
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Security Circuit Eschews
Sophistication:
05/26/94 EDN-Design Ideas |
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Signal Detecting Auto Power On
Unit: |
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Simple circuit shuts off system
when supply voltage is low:
05/12/97 Electronic Design - Ideas for Design /
Many low-cost and portable systems, including
small consumer electronic products, operate from
unregulated power supplies such as batteries or
external, plug-in “power bricks.” These power
sources sometimes produce lower-than-nominal
output. . . |
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Simple soft-start circuit for switching regulators:
07/21/97 Electronic Design - Ideas for Design /
In the early stages of development, one of the
many issues circuit designers must evaluate is
how the circuit behaves when power is first
applied. Unexpected things can happen at
startup. All capacitors must be charged and all
ICs change from an. . . |
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Simple switchers make simple
pre-regulators:
07/07/97 Electronic Design - Ideas for Design /
Linear regulators are used extensively because
of their simplicity, low cost, quiet operation,
and clean outputs. In applications where the
output voltage must be adjusted over a wide
range, however, they can dissipate considerable
power and require. . . |
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Sleeping Aid
: Based on electromagnetic-field
radiation Place it under the pillow-Built-in
Timer |
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Smart Foot Switch:
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Soft On / Off Switch:
Modern electronic equipment incorporate
"push-to-on-push-to-off" switches that do not
make the clicking noise as with old equipment.
An example of this is the power button on a ATX
computer cabinet. Here is a circuit that does
the same. It can be used to turn on/off any
electronic/electrical equipment that operates on
any range of voltages. FAIR WARNING -- THIS SITE
HAS ANNOYING POP UP ADS. |
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Solid State Relay Saves Battery's
Life: 09/01/94 EDN-Design
Ideas |
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Solid State Switch for DC
Operated Gadgets: |
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Sound Operated Switch:
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Stop / Start Circuit using a
Relay & Pushbutton Switches:
for use when you want to manually restart a
device after a power failure |
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Switch Circuits:
collection of Switch Circuits for temperature,
light level and button controlled switching
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Switch debouncer uses only one
gate: 05/30/2002 EDN
- Design Ideas / The circuit in Figure 1
produces a single debounced pulse each time you
press S1. Moreover, the circuit uses only logic
power from the remote pull-up resistor, R2. You
can use the circuit to detect when a key is
pressed in a nonenergized device, such as a
device in a system that's just coming up from
standby |
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Switch on Delay Circuit: |
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Switch-Debouncer IC Creates A
Long-Period Timer:
10/01/01 Electronic Design - Ideas for Design /
One major application for long-period timers is
in remote weather-data stations. These stations
measure environmental conditions at regular time
intervals and transmit the results to a central
collecting facility. Since these small weather
stations. . . |
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Thermal switches provide circuit
disconnect :
09/04/03 EDN-Design Ideas / A single
temperature sensor can provide an interrupt to a
microcontroller when the measured temperature
goes out of range. You need multiple temperature
sensors when you have to monitor more than one
hot spot. A microcontroller implements the
proper protective action when one of the
temperature monitors detects an overtemperature
condition.... |
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Three parts provide tenfold
increase in switcher current:
08/22/2002 EDN - Design Ideas /
Industrial-control circuits often derive their
power from widely varying sources that can
exceed the 40V maximum rating of popular
switching ICs. This Design Idea presents a
simple, flexible, and inexpensive buck switcher
that converts an input voltage as high as 60V to
5V at several amps. The circuit is unique in
that it boosts current with almost no compromise
in performance, size, or cost.. |
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Three Way Touch Lamp:
A three-way switch to control a lamp
(off-dim-bright, etc.) uses an NE555 Timer to
generate a1-second pulse, triggered by ambient
ac fields that are picked up by the human body.
Read also the circuit description.
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Time Switch: |
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Time Switch:
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Toggle Switch Debounced
Pushbutton: |
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Touch Activated Alarm: |
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Touch Dimmer:
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Touch Switch #2: |
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Touch Switch #3:
This is achieved using a jugfet, it is a very
simple circuit and very effective to with a
minimum component count working via a 1.5v cell. |
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Touch Switch #4:
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Touch Switch using Transistors:
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Touch Switches: |
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Triac Light Controller:
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Two buttons provide safe start:
07/06/00 EDN-Design Ideas / Provides a safety
interlock that checks the actuation of two
pushbuttons before enabling a relay. When you
push both buttons, the circuit actuates the
relay. At that point, you can release one of the
switches without the relays switching off. The
circuit was intended to lock out the engine of
an underwater propulsion unit. |
|
Two Line Intercom Plus a
Telephone Changeover Switch:
The circuit presented here can be used for
connecting two telephones in parallel and also
as a2-line intercom. FAIR WARNING -- THIS SITE
HAS ANNOYING POP UP ADS. |
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Use a tiny microcontroller with a
large keypad:
09/02/97 Electronic Design - Ideas for Design /
Like a student needing just one more night to
prepare for a coming exam, a microcontroller
designer often wishes for just one more I/O line
as a project approaches its final stages. Even
for the relatively capable 8X752 microcontroller
at 28 pins,. . . |
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Video monitor adapter enhances
oscilloscope:
08/18/97 Electronic Design - Ideas for Design /
Video signals can be difficult to display on an
oscilloscope. Normal trigger circuits in most
oscilloscopes have trouble getting a stable
trigger from the combined vertical and
horizontal sync signals, color burst, and
picture signal in a composite. . . |
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Video Routers:
VISW 8 x4 Stereo audio/video router
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Video Stabiliser
: |
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Video Switch:
This article (published in Circuit Cellar
Magazine) describes a circuit which switches RGB
signals between two genlocked cameras. This
project used analogue switched and programmable
logic (programmed using VHDL). This article is
also available in PDF format and in zipped
packet from Circuit Cellar Apr1999.
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VISW 8 x 4 Stereo Audio / Video
Router :
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VOICE CONTROLLED SWITCH: This is a slightly
more harder circuit than some of the others with
a higher component count but still very
interesting. |
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Voice Over Circuit:
switches automatically from sound source to
microph1-when enough sound comes in from
microph1- |
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Voltage Comparator Switch:
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Water Activated Relay: |
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Whistle On Whistle Off:
This CMOS toggle flip flop circuit has an
addition of two bandpass filters and condenser
microph1-so the relay can be toggled by
whistling at it. |
|
Whistle Responder:
Beeps when hears your whistle A gadget suitable
for key-holders, games etc. |
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Whistle Switch:
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X Y Keypad uses �C's Serial Port:
10/10/96 EDN-Design Ideas |
