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Last Updated
03/31/2019
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Detailed entries for one subject from the INDEX TO HOW TO DO IT INFORMATION. |
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RELAY sa REMOTE CONTROL xx ELECTRONIC COMPONENT xx REMOTE CONTROL xx SWITCH Advice on using mercury-wetted reed relays for low-level audio switching. Relays for loudspeaker protection. Everything you need to know about electromechanical relays to help you design better circuits to protect the speaker if the amplifier fails. How to wire several optically isolated solid state relays to a parallel output port of your computer. Use them to control electric devices up to 10 amps (110 volts) by turning them on and off at programmed times. Est. cost: $20 per controller. Switching inductive vs. resistive loads with relays. Manipulating relays. (1) Delaying pull-in time. (2) Faster pull in. (3) Using a relay as a resettable circuit breaker. (4) Latching a relay. Time delay relay. This device will drive a 3-ampere AC load for a specified period of time (a few seconds up to an hour), and then shut off the load automatically. All about relays. Part 1. Basic operating principles and application rules for electromagnetic relay (EMR), reed relay, solid-state relay (SSR) and the CMOS bilateral switch. All about relays. Part 2. Selection of practical control circuits for electromagnetic relays. Power semiconductors. Part 1. An overview of transistors, thyristors, solid-state relays, and integrated circuits which have been designed to switch high currents and voltages. Power semiconductors. Part 2. Power control circuits. Learn to apply power semiconductors in practical power control circuits. Use them to control appliances, motors, and relays. Latching-switch circuit uses a flop-flop IC. Can be used to replace a mechanical relay latch circuit. Simple interface circuit which allows each data bit of a PC's parallel port to control a relay. Special section on the selection and use of relays. Multiple-function remote-control relay circuits can sense and control high-power circuits. Push-on/push-off electronic switch uses a flip-flop circuit to drive a relay that has switching contacts to handle the load you want to control. Schematic diagram for a time-delayed relay. Circuit for a relay interface to drive large numeric readout devices, such as those found in sports scoreboards. Modification to a TTL logic controlled alarm circuit adds a protection diode around the relay coil to prevent transistor blowout from current overload during relay switching. Circuit which will energize a relay for about one second each minute, but with a control which allows the time interval to be adjusted from 57 to 63 seconds. Schematic for a circuit which will allow a 12-volt relay to close a circuit and then shut it off after five minutes. Uses a 555 type IC. A multi-function oscillator circuit uses two transistors. Applications include a code-practice oscillator, lamp and LED flashers, audio oscillator, dc-to-dc upconverter, relay control, and pulse generator. Transistorized circuit to latch relays and other control devices. Very sensitive electronic relay for use in alarms, controls, etc. Control circuit uses ability of diode to rectify AC and to block DC of reverse polarity. Thus a 2-wire control line is used to operate any of three relays. Make your own reed switch relay. Low-cost isolation relay is ideal for experimenters. Use it to build (1) a magic electric lamp you light with a match, (2) light-activated remote sound shut-off for TV commercials, and (3) slot-car lap counter. Circuit for controlling three sequential functions using only a variable DC source. Uses Zener diodes in conjunction with three relays. Circuit for turning a relay on and off at selected intervals up to 5 seconds. Low-cost time delay relay can handle up to 1000 watts, 115 volt AC. Delay time of 4 seconds to 6 minutes. Circuit provides visual indication of whether a relay is open or closed. How to use solid-state circuits to obtain predictable performance from electromechanical relays. An experimenter's guide to relay control. Relay controller circuit uses a power hexFET. Winning the relay race. How relays have evolved through the years to survive both tube and transistor eras. Includes a reference glossary of relay types. Relay debouncer circuit uses an optoisolator. A failsafe bipolar relay driver is used to complete the relay's coil circuit after sensing a pulse-on signal from a computer, or other source. Simple circuit is a great help in checking solenoids and relays. Relay controller. A double-pole, double-throw relay wired for latching operation. Relay actuator circuit uses just two inexpensive switches instead of a hex converter. Simple circuit called a delay-off relay timer. A charged capacitor keeps a relay latched. This can provide an exit delay for an alarm system. How to use the popular 555 timer IC in practical monostable multivibrator circuits. (1) Fixed-period timer. (2) Relay drivers. (3) Pulse generator. (4) 1-kHz linear-scale analog frequency meter. Simple single-transistor circuits. (1) Voltage regulator outputs 6-volts DC. (2) Constant-current output. (3) Simple audio amplifier. (4) Impedance-matching circuit. (5) LED-control circuits turn either off or on in the presence of a DC voltages from 5- to 9-volts. (6) Relay-driver circuit has a latching feature that keeps the relay on once energized. Simple diode circuits. (1) Bridge rectifier. (2) Sound-level (audio signal) limiter circuit never exceeds 1.5-volts peak-to-peak. (3) DC polarity or AC indicator circuit. (4) Kick-back voltage limiter for inductive loads. (5) Steering circuit controls relays based on voltage polarity. (6) Simple temperature sensor. (7) Circuit for selecting matching diodes. Simple op-amp application circuits. (1) Fixed voltage reference. (2) Light-operated sensor. (3) Alarm sensor. (4) Voltage-level sensor. (5) Peak-voltage detector and hold. (6) DC motor driver and reverser. (7) Simple timer circuit to delay relay operation for up to 30 seconds. Tip: An explanation of the operation of a three-pole relay. Circuit for a relay multivibrator. Circuits to alternately open and close a relay on sequential control pulses. Tip: How to avoid stray signal paths when a multiple-input circuit controls several different relays. More control circuits. Using relays as alternatives to manual switches. All about transistor switches. How to control motors, relays and light bulbs with digital IC's. Understanding relays. Part 1. Electromechanical versions. Understanding relays. Part 2. Solid-state versions. Circuit built around a 555 timer IC and a 4017 IC are used to trigger up to ten relays that in turn control AC power. The circuit shown is designed to operate a decorative traffic light (or similar device). Controlling an inductor (such as a relay or motor coil) using a solid-state device requires special protection techniques. Three transient (spike) suppressor circuits shown. Solid state relays (SSR's). Build your own repairable SSR's that interface low-power digital logic to 115-volts AC (or higher). Est. cost: $8. Convert any lever-type telegraph key into a simple relay. Schematic for a 24-volt switch with indicator light that is used to activate a 220-volt air compressor via a relay (2-pole contactor). | |||||||||
Copyright © by Norman Lathrop Enterprises. All Rights Reserved. No part of this publication may be reproduced, stored in a retrieval system or transmitted, in any form or by any means (electronic, mechanical, print photocopying, recording or otherwise) without the prior expressed permission of Norman Lathrop Enterprises, except as permitted by law. |
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