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A Current Limiting Bench Power Supply - Power Supply Circuits: This is a 1-amp variable-voltage PSU. it adjusts from about 3v to 24v: and has the added feature that you can limit the maximum output current. This is invaluable when (for example) you power-up a project for the first time or soak-test a piece of equipment. __ Designed by Ron J.
A Low Power RF ID Transponder - This is the Grand Prize winner in the design category of the 1993 RF Design Awards Contest. This entry exhibited both innovative use of RF technology and an elegant implementation of that technology __ Designed by Raymond Page
A One-Time-Only Burglar Alarm - Multi-Zone Burglar Alarm Circuits: When this alarm is activated its Siren will sound once - for up to 20-minutes. Then it will switch off and remain off. The basic circuit has a single zone with independently adjustable Exit and Entry delays. This will be adequate in many situations. However, there's also a range of Expansion Modules. These will allow you to add any number of instant Zones, Tamper Zones and Personal Attack Zones to your system. __ Designed by Ron J.
A SCR Based Burglar Alarm - This is a simple SCR based burglar alarm circuit. its features include automatic Exit and Entry delays - together with a timed Bell cut-off and Reset. it's designed to be used with the usual types of normally-closed input devices such as - magnetic-reed contacts - micro switches - foil tape - and PiRs __ Designed by Ron J
A Shed / Garage Alarm - Battery-Powered Alarm Circuits: This is a basic single-zone burglar alarm circuit. its features include automatic Exit and Entry delays - and an optional Siren Cut-Off timer. it has an extremely small standby current. This makes it ideal for battery-powered operation. Use it in your caravan, mobile home, lock-up, or anywhere mains power is not available. __ Designed by Ron J.
A Simple Circuit Fire-Door Alarm - Battery-Powered Alarm Circuits: This circuit will let you know when something that should be kept closed - has in fact been left open. if you attach it to say a Fire-Door - it will allow you to pass back and forth freely. it's only when the door is open for more than about 30-seconds - that the buzzer will sound the alarm. The Page includes a free SiMetrixcircuit simulation. __ Designed by Ron J.
A Simple Circuit Shop-Door Alarm - Battery-Powered Alarm Circuits: Attach this circuit to the door of an unattended shop or reception area - and the sound of the buzzer will tell you when you have a customer. Add a siren - and it becomes a simple intruder alarm. The Page includes a free SiMetrix circuit simulation. __ Designed by Ron J.
A Simple Circuit Transistor Based Motorcycle Alarm - Motorcycle Alarm Circuits: This is an even simpler transistor based motorcycle alarm. The circuit features a timed output and automatic reset. it can be operated manually using a key-switch or a hidden switch. By adding an external relay, it will set itself automatically - and/or immobilize the machine - every time you turn-off the ignition. it's easily adapted for a 6-volt system - so it will protect your "Classic Bike". - Now With Free SiMetrix Circuit Simulation. __ Designed by Ron J.
A Simpler CMOS
Single Zone Alarm - Single-Zone Burglar Alarm Circuits: This circuit features automatic Exit/Entry delays, timed Bell Cut-off and System Reset. it will accommodate the usual normally-closed input devices (Magnetic Reed contacts, Micro Switches, Foil Tape and PiRs). And - with a simple modification - a normally-open trigger may be added. __ Designed by Ron J.
A Transistor Based Burglar Alarm - This is a simple transistor based burglar alarm circuit. its features include automatic Exit and Entry delays - together with a timed Bell cut-off and Reset. it's designed to be used with the usual types of normally-closed input devices such as - magnetic-reed contacts - micro switches - foil tape - and PiRs. __ Designed by Ron J.
A Transistor Based Motorcycle Alarm - Motorcycle Alarm Circuits: This circuit features a timed output and automatic reset. it can be operated manually using a key-switch or a hidden switch. By adding an external relay, it will set itself automatically - and/or immobilize the machine - every time you turn-off the ignition. it's easily adapted for a 6-volt system - so it will protect your "Classic Bike". - Now With Free SiMetrix Circuit Simulation. __ Designed by Ron J.
A Transistor Based Single Zone Alarm - Single-Zone Burglar Alarm Circuits: The circuit features automatic Exit and Entry delays, timed Bell Cut-off and System Reset. it has provision for normally-open and normally-closed switches and will suit the usual input devices (Pressure Mats, Magnetic Reed contacts, Foil Tape, PiRs and inertia Sensors). __ Designed by Ron J.
Alarm control keypad - The IC is a quad 2 input "AND" gate, a CMOS
4081. These gates only produce a HiGH output, when BOTH the inputs are HiGH. When the key wired to 'E' is pressed, current through R1 and D1 switchs Q5 on. The relay energises; and Q5 is 'latched on' by R8. Thus, the Alarm is set by pressing a single key, say one of the two non-numeric symbols __ Designed by Ron J.
Alarm Discriminator + Battery Monitor of the Electric Field Disturbance Monitor - This schematic is the alarm discriminator plus the batterry monitor of my "Electric Field Disturbance Monitor". The system can detect human and animal motion by the electric fields they disturb . . . Hobby Circuit designed by Dave Johnson P.E.-March, 2002
Alarm Sounds when Phone Line is Cut - Burglars, rapists and other criminals will often cut a phone line before they break into a home. The cut phone line will prevent many alarm systems from alerting the police. The battery powered circuit below will sound an alarm when the unit . . . Hobby Circuit designed by David Johnson P.E.-October, 2005
Ambulance Siren - This siren circuit simulates police, fire or other emergency sirens that produce an up and down wail. __ Contact: Charles Wenzel of Wenzel Associates, Inc.
An Enhanced Shed / Garage Alarm - Battery-Powered Alarm Circuits: This is an enhanced version of the simple Garage/Shed Alarm. The Entry and Exit delays have been increased to about 30-seconds - and I'veadded a timed Siren cut-off and automatic Reset. I'vealso replaced the LED with an entry Buzzer. These enhancements mean that the new version will have a much wider application. __ Designed by Ron J.
An Expandable Multi-Zone Modular Burglar Alarm - Multi-Zone Burglar Alarm Circuits: This circuit features automatic Exit and Entry delays and a timed Bell Cut-off. it has provision for both normally-closed and normally-open contacts, and a 24-hour Personal Attack/Tamper zone. By using the Expansion Modules, you can add as many zones as you require; some or all of which may be the inertia (shock) sensor type. __ Designed by Ron J.
An Expandable Transistor Based Burglar Alarm - Multi-Zone Burglar Alarm Circuits: This transistor based alarm features automatic Exit and Entry delays - together with a timed Bell Cut-off and system Reset. Along with the Exit/Entry zone - the basic alarm board has one instant Zone. This will be adequate in many situations. However - the modular design means that it's easy to add as many zones as you like to the system. Details of a Four-Zone expansion module are provided. __ Designed by Ron J.
Anti Theft Motorcycle Alarm - Any number of normally open switches may be used. Fit the mercury switches so that they close when the steering is moved or when the bike is lifted off its side-stand or pushed forward off its centre-stand. Use micro-switches to protect removable panels and the lids of panniers etc. While at least one switch remains closed, the siren will sound. About two minutes after the switches have been opened again, the alarm will reset. __ Designed by Ron J
Anti-Bag-Snatching Alarm - Here is a simple alarm circuit to thwart snatching of your valuables while travelling. The circuit kept in your bag or suitcase sounds a loud alarm, simulating a police horn, if...__ Electronics Projects for You
Anti-Bag-Snatching Alarm - Small, portable, anti-bag-snatching unit. Also suitable for doors and windows control.__
Anti-Carjack System - Consider this: A criminal stops your car by force and you are left with no option but to surrender the car. The criminal drives away your car, but about 60 seconds...__ Electronics Projects for You
Anti-theft Car Alarm - Here is a simple AntI theft car alarm device for your Car. it generates a loud alarm when there is an attempt of theft. When the intruder opens the door, the circuit senses the attempt of theft and after 2 minutes, the alarm will be activated. The time delay is provided to help the user to leave the car after arming with the __ Designed by D Mohankumar
Anti-Theft Security for Car Audio - This small circuit, based on popular CMOS
NAND chip CD4093, can be effectively used for protecting your expensive car audio system against theft. When 12V DC from the car battery is applied to the gadget (as indicated by
LED1) through switch S1, the circuit goes into standby mode. LED inside optocoupler IC 1 is lit as its cathode terminal is grounded via the car audio (amplifier) body. As a result, the output at pin 3 of gate N1 goes low and disables the rest of the circuit. __ Learning Electronics
Arduino Panic Alarm - Here is the circuit of an Arduino-based Panic Alarm! The wiring is very simple so that even a novice can construct this interesting circuit without any difficulty. Arduino is a family of microcontrollers (tiny computers) and a software creation environment (Arduino iDE) that makes it easy for you to create programs (called __ Designed by T.K. Hareendran
Audio Amplifier Protection - Now you can protect your HiFI amplifier from damage due to excess heat. This circuit will cut off the power to the amplifier board at the moment it senses a high temperature. it automatically connects power when the temperature returns to normal. The circuit uses an NTC Thermister as heat sensor and it also has audible warning __ Designed by D Mohankumar
Automatic Door Opener with PIC12c508 - This circuit can be used to operate an electric strike or an electromagnetic lock on a door. it is not the door being opened/closed, but a small electromagnetic strike which unlocks the door. The opener has the following features currently programmed in software __ Designed by Peter Jakab
Automatic Emergency Light - This circuit implements the concept of emergency light through relays. The circuit lights up LEDs in case of power failure and charges the batteries otherwise. __ Contact IQ Technologies
Automatic emergency torch - Just don’t think that this is yet another addition to other emergency light circuits published in EFY earlier. This circuit is a hit different. __ Designed by bhgya parma
Automatic Intruder Alarm - This is a simple single-zone burglar alarm circuit. its features include automatic Exit and Entry delays and a timed Bell/Siren Cut-Off. it's designed to be used with the usual types of normally-closed input devices such as - magnetic reed contacts - micro switches - foil tape - and PiRs. But it can be Easily Modified to accept normally-open triggering devices - such as pressure mats. __ Designed by Ron J
Automatic Room Lights - An ordinary automatic room power control circuit has only one light sensor. So when a person entersroom it gets one pulse andlights come ‘on. ’ Whenperson goes out it gets anor pulse andlights go ‘off. ’ But what happens when two persons enterroom, one afteror? it gets two pulses andlights remain in ‘off’__
Automatic Room-Lock & Lights Circuit - This circuit counts and indicates up to nine persons present in the room and automatically locks the door and switches off lights as soon as they leave. it automatically switches on...__ Electronics Projects for You
Automatic School Bell - Consider that a school has a total of eight periods with a lunch break after the fourth period. Each period is 45 minutes long, while the duration of the lunch break...__ Electronics Projects for You
Automatic Solar Garden Lights with LEDs - Efficient automatic solar garder lights circuit with minimum components the best deal is that is completely auto and the Solar panel acts as a light detector. Switches the Lamp off at Dawn, charges the battery during daytime and switches the LED lights ON at dusk providing 100 Lumens illumination during the night. The solar __ Designed by Sebastian Kushero |
