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  • Automatic vehicle alarm

    2016-02-18 20:57:4862

    In operation, the alarm circuit may have a time delay of 0-47 seconds, the combination of RL / CL, the switch can be mounted to the vehicle motion sens...

  • Automotive security alarms

    2016-02-18 20:51:0965

    The Automotive alarm circuit when you close the door or open other sensorswitches the alarm condition remains. The alarm circuit for the circuit to pro...

  • Door open beeper alarm

    2016-02-18 20:15:2081

    When door is opened, the beeper is enabled by the logic high state and the speaker starts beeping intermittently at a rate of about 0.5 secs on/0.5 sec...

  • Car Alarm Simulator circuit diagram

    2016-02-18 20:05:2066

    This is a car alarm simulator which using the LED as a simulation output. This simple circuit can tell you whether your car is running or not by detect...

  • Water Level Indicator with Alarm

    2016-02-18 19:41:2874

    This is a Water Level Indicator with alarm circuit. This circuit is used to indicate the amount of water present in the overhead tank. Not only that, b...

  • Wide-frequency-ttl-clock

    2016-02-18 19:35:1366

    This free-running TTL square-wave oscillator has a variable frequency output over a 20:1 range or better through use of four of the six inverters in an...

  • Rain warning beeper

    2016-02-18 19:28:3263

    One small spot of rain on the sense pad of this bleeper will start this audio warning. It can also be operated by rising water. The circuit has two tra...

  • alarm keypad - enhanced 5 digit

    2016-02-18 19:10:1362

    This article describes the enhanced keypad five alarm circuit. For your better understanding in the diagram, we recommend that you look at the text. Wo...

  • How to build Remote Alarm For Smoke Detector

    2016-02-18 19:00:2263

    Description This alarm circuit was designed to monitor a mains-powered smoke detector located in a shed (which is used to house dog kennels). It provid...

  • Warbling Wailing Alarm Siren Circuit

    2016-02-18 18:59:5175

    This alarm siren circuit give continuous frequency sweep, a warbling sound. The warbling period is about 6 seconds, 3 seconds for frequency sweeping up...

  • Flood Alarm

    2016-02-18 18:56:5366

    Using a few bipolar transistors, this circuit acts as a flood alarm. When liquid touches the probes, leakage current biases Ql, Q2, and Q3 (a dc-cou-pl...

  • Car Alarm and Immobilizer

    2016-02-18 18:49:2567

    Description: This circuit features exit and entry delays, an instant alarm zone, an intermittent sirenoutput and automatic reset. By adding external re...

  • Two Tones (Ambulance) Alarm Circuit

    2016-02-18 18:47:1371

    Using very popular multivibrator 555 IC, we can build an alarm circuit which is similar to old ambulance siren. There are two sections inside the circu...

  • Minute Timer with alarm by IC555

    2016-02-18 18:45:1885

    This circuit uses a 555 IC timer number.This small, compact and portable. For the snooze alarm when some 10 or 15 minutes.It makes clear the brain is r...

  • Forget door alarm circuit

    2016-02-18 18:42:55156

    This circuit uses to warn when forget shut the door. By use switch stick at the door, if do not shut the door switch will off as a result will have a v...

  • A modular burglar alarm circuit

    2016-02-18 18:41:0788

    The article describes a modular burglar alarm circuit. The circuit is very simple, very helpful. If you understand this principle is not very thorough,...

  • Selective timer alarm.

    2016-02-18 18:36:1673

    Description. A timer circuit using IC 4060 is given here. The IC 4060 is a 14 stage binary counter with a built-in oscillator.R2, R7, C1 are the compon...

  • A low voltage alarm circuit

    2016-02-18 18:30:2166

    This article describes a low voltage alarm circuit. This circuit is not new, but it proved so useful, simple and cheap, it is worth building. This circ...

  • Water Alarm Circuit (4093)

    2016-02-18 18:27:4781

    This article briefly describes the Water Alarm Circuit (4093). This principle is easy to understand, but also very practical. Depth understanding of ci...

  • Smoke Alarm Battery Life Extender

    2016-02-18 18:25:3063

    While smoke alarms are quite cheap devices, the cost of 9V batteries quickly exceeds their purchase price. Added to that is the irritation of random be...

  • Miniature Loop Alarm

    2016-02-18 18:19:2964

    A few months ago, I decided to build a compact, yet effective alarm. My demands were:- simple construction, reliable operation, very small power consum...

  • Step Alarm Circuit

    2016-02-18 18:01:4969

    This Circuit can monitor the door steps or Staircase. When a person crosses the steps, the alarm sounds indicating the entry. The circuit is too sensit...

  • Invisible Infrared Alarm Circuit

    2016-02-18 17:51:1270

    This circuit uses Invisible Infrared light to detect the movement of people through the door. A short beep will be generated when the infrared beam bre...

  • Rain alarm-door bell

    2016-02-18 17:48:3096

    With SI open the circuit functions as a doorbell. With SI closed, rain falling on the sensor will turn on Ql, triggering Q2 and the thyristor and activ...

  • Door Alarm Circuit

    2016-02-18 17:27:3367

    Optical Door Alarm Circuit Here is an opticaldoor alarm circuitis easy to build and can be used in a variety of alarm applications. The compact alarm c...

  • Ford Probe Single Wire Door Lock/Unlock Alarm System Circuit

    2016-02-18 17:25:2066

    The following circuit schemes the Ford Probe Single Wire Door Alarm System. This Single Door Locking Wire controls both LOCK and UNLOCK which means the...

  • Automatic burglar alarm circuit

    2016-02-18 17:08:1675

    The article describes the automatic burglar alarm circuit. The circuit is very simple, very helpful. If you understand this principle is not very thoro...

  • Car Auto Arming Alarm circuit

    2016-02-18 16:59:3466

    The car alarm here is a simple circuit with basic characteristics that cover all entrances at the car that has switches (doors etc).With one switch (ar...

  • Audible Flasher Warning

    2016-02-18 16:55:0866

    If youre a biker or scooter rider youll know how easy it is to forget to cancel your flashing indicators after turning without an audible reminder. Con...

  • Refrigerator Alarm Circuit

    2016-02-18 16:33:5663

    Use this refrigerator alarm circuit to prevent leaving the fridge door open by sending out an alarm signal every time the door is left open for some ti...

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