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1 min to 20 hrs Long Duration Relay - (electronic schematic added 08/08/08) |
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12 Sec to 90 min Relay - (circuit / schematic added 2/06) |
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122 Volt AC Lamp Chaser using Solid State Relays - This circuit is similar to
LED clock using12 neon indicator lamps instead of LEDs. It operates from2 high
capacity ni-cad cells (2.5 volts) which keep it going for a couple weeks. High voltage
(70 volts) for neon lamps is obtained from a small ...(added 4/02) |
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2 Lead Solid State Breaker Resets Itself - 03/30/95 EDN-Design Ideas / (added
03/03/03) Simple dc circuit breaker can protect a power supply from ever-present
screwdriver or even isolate a satellites dual power system from a short circuit in one
subsystem |
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4 channel infrared remote relays - ….(circuit design added 08/08) |
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555 Timer MonoStable Circuit using Pushbutton - The two circuits above illustrate
using the 555 timer to close a relay for a predetermined amount of time by pressing a
momentary N/O push button. The circuit on the left can be used for long time periods
where the push button can be pressed and released before the end of the timing period.
For shorter periods, a capacitor can be used to isolate the switch....(electronic
schematic / circuit added 4/02) |
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741 Based Light Sensor - CdS photocell used for light/dark controlled relay (added
5/02) |
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8 Channel LPT relay board - Channel Relay Board is a simple and convenient way to
interface 8 relays for switching application in your project…..(electronic design idea
added 09/08) |
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9 Second LED Relay Timer - This circuit provides a visual 9 second delay using a 7
segment digital readout LED. When the switch is closed, the CD4010 up/down counter is
preset to 9 and the 555 timer is disabled with the output held high. When the switch
is opened,....(circuit / schematic design added 6/06) |
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AC Line Current Detector - This circuit will detect AC line currents of about 250
mA or more without making any electrical connections to the line. Current is detected
by passing one of the AC lines through an inductive pickup (L1) made with a 1 inch
diameter U-bolt wound with 800 turns of #30 - #35 magnet wire. The pickup could be
made from other iron type rings or...(electronic schematic / circuit added 4/02) |
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Alternating on/Off Control - This circuit uses three easily available 555 timer
ICs. All three work as astable multivibrators. The first 555 has an on period and off
period equal to 1 sec. This IC controls on/ off periods of or 2 555s which
are used to flash two bulbs through relay contacts..... (added
10/05) |
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Analog Switch Lowers relay Power consumption - 12/20/01 EDN Design Ideas /
(added 1/05) Designers often use relays as electrically controlled switches.
Unlike transistors, ir switch contacts are electrically isolated from control
input. However, power dissipation in a relay coil may render device
unattractive in battery-powered applications. You can lower this dissipation by adding
an analog switch that allows relay to operate at a lower voltage (Figure 1).... |
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Assorted relay Control circuits - (electronic circuit added 4/05) |
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Basic Solid State Relays - (electronic circuit added 05/06/07) |
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Basic Stamp I and PC Relay Controller - (electronic circuit added 4/05) |
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Bidirectional Solid State Relay - The circuit below can switch up to 4 amps of
current with a peak voltage up to 20v. It is fully isolated using two inexpensive red
LEDs. One LED forms a red light source, which illuminates a second red LED. The
circuit takes advantage of the 1.5v produced by super bright red LEDs when illuminated
with red light. The voltage produced by one red is routed to two n-channel
FETs,.….(designed by David A. Johnson) |
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Charge Coupled Bi-Directional Power Mosfet Relay - The circuit uses an inexpensive
C-MOS inverter package and a few small capacitors to drive two power MOS transistors
from a 12v to 15v supply. Since the coupling capacitor values used to drive the FETs
are small, the leakage current from the power line into the control circuit is a tiny
4uA. Only about 1.5mA of DC is needed to turn on and off 400 watts of AC or DC power
to a load. Published in Electronic Design, Nov. 8, 1990. ….(designed by David A.
Johnson) |
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Circuit Drives Latching Relays - 02/01/96 EDN-Design Ideas / (added 3/03)
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Circuit removes relay contact Bounce - 11/27/03 EDN Design Ideas /
(added 1/05) Advances in semiconductor technology have allowed ICs to replace
many mechanical relays, but relays still dominate in high-current circuits that must
stand off high voltages of arbitrary polarity. Contact bounce in those relays,
however, can prove troublesome to downstream circuitry. One approach to contact bounce
combines a relay with a hot-swap controller.... |
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Circuits protect outputs against overvoltage - (Design Ideas - EDN, 10/11/2007
Adding a solid-state relay and control circuitry to an amplifier's output provides
overvoltage protection. (electronic design idea added 10/07) |
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Clap Relay - Clap sensitive on-off Relay. 3V Battery operated, small
portable unit, (added 6/06) |
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CMOS Toggle Flip Flop using Push Button CD4013 - 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.... (added 10/05) |
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Control 120 Volt AC Relay with TTL - ASCII format (electronic schematic / circuit
added 4/02) |
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Control 120VAC relay with TTL - ASCII format (circuit design added 11/06)
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Controlling Relays with Logic Voltages - (electronic schematic / circuit added
4/02) |
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Countdown timer with Relay - (design added 8/03) |
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Dancing LEDs redcircuits - A LED sequencer, following the rhythm of music or
speech 9 Volt Battery-operated portable unit (added 9/04) |
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Dark/Light Activated Relay - The potmeter adjust the trigger 'on' level. The
diode in the diagram shows to be 1N914. This is ok if you have a light-duty
relay, also the 1N914 is a signal diode so actually does not qualify. Use a
1N4001 (or better) instead. A couple of substitutes for the 2N2222 transistor
are: NTE123A, ECG123A, PN100, etc. (schematic / circuit added 10/02) |
Dual Relay Driver Board - We have used two Goodsky RWH-SH-112D 12V relays, coil
resistance 400 ohm. It is rated to switch 250VAC at 12A. However, because of the PCB
track thickness and width we do not recommend using the
relay to switch more than 5A. If you….(design idea circuit added 09/08) |
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Electronic relay - In some applications where you require speed of operation
and no contact bouncing, you may find this circuit helpful. This is really the
implementation of an SCR with discrete components. The medium power complementary pair
will switch on and off a load up to 3A. You may modify the circuit to carry up to 10A
using suitable power transistors and diodes. The left side ... (added 9/07) |
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Electronic Thermostat Relay Circuit - Here is a simple thermostat circuit that can
be used to control a relay and supply power to a small space heater through the relay
contacts. The relay contacts should be rated above the current requirements for the
heater. Temperature changes are detected by a (1.7K @ 70F) thermistor placed in series
with a 5K potentiometer which produces about....(electronic schematic / circuit added
04/03/02) |
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Electronic Toggle Switch No.1 - This simple circuit will energize and de-energize
a relay at the push of a button. Pushing the button once - will energize the relay.
And pushing it a second time - will de-energize the relay. The accompanying Circuit
Description offers a good introduction to the workings of the Cmos 4013.
(circuit design add 02/09) |
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Electronic Toggle Switch No.2 - This simple circuit will energize and de-energize
a relay at the push of a button. Pushing the button once - will energize the relay.
And pushing it a second time - will de-energize the relay. The accompanying Circuit
Description offers a good introduction to the workings of the Cmos 4013.
(circuit design add 02/09) |
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Generating a Delayed Pulse with a Dual 555 Timer - The circuit below illustrates
generating a single positive pulse which is delayed relative to the trigger input
time. The circuit is similar to the one above but employs two stages so that both the
pulse width and delay can be controlled. When the button is depressed, the output of
the first....(schematic added 8/03) |
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Inexpensive Relays Form Digital Potentiometer - 03/13/98 EDN-Design Ideas / (added
6/06) -Build a digitally controlable isolated potentiometer that can
tolerate voltages up to 60-Volt dc |
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Infrared Relay with Relay Output - (electronic circuit added 4/05) |
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KD2BD Video Operated Relay - turns on relay if there is video signal present in
the input (added 5/02) |
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Key reading circuit saves I/O pins - 02/06/03 EDN-Design Ideas / (added
8/03) Some microcontroller applications usually use too many I/O pins to read keys or
onboard switches; in many cases, few pins remain available for other uses. Some
alternative ways to read keys yield more free pins. First, consider some ways to
effect key .... |
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LED Relay Timer - This circuit provides a visual 9 second delay using a 7 segment
digital readout LED. When the switch is closed, the CD4010 up/down counter is preset
to 9 and the 555 timer is disabLED with the output held high. When the switch is
opened,....(circuit / schematic design added 6/06) |
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Light Activated Relay (Bowden) - This is same circuit as above with the addition
of a photo resistor to trigger the flip flop instead of a push button. The bias
resistor in series with photo resistor was chosen so that sufficient voltage is
present at the base of the 2N3904 to supply current to the circuit in ambient lighting
conditions...(electronic circuit added 4/05) |
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Light Sensor - 741 Based - CdS photocell used for light/dark controlled relay
(added 5/02) |
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Light/Dark Detector (Aaron Cake) - This handy little circuit can tell the
difference between darkness and light, making it very useful for switching on and off
signs, porch lights or other things when it gets dark or light. (circuit / schematic
design added 04/03/02) |
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Load Sensing Automatic Switch - apply power to the entire audio system by turning
on1-item, simple circuit (added 5/02) |
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Maximizing the Life Span of Your Relays 5988-6917EN - Aligent Application Note
1399 (added 4/08) |
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Modular Relay System - This is simple transistorised relay into which can be
plugged 'personality modules' to turn the base unit into a timer (pulse, delay on
energise or delay on de-energise) or a latching relay or whatever is required. This is
therefore a universal relay system. It was designed to simplify industrial machinery
control....(electronic schematic / circuit added 4/02) |
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Multiple Relay Drive - Circuit Ideas for Designers Application Notes Advanced
Linear Devices, Inc. (app note added 6/06) |
