Low cost fire alarm circuit.

admin January 21, 2014 89 Comments
Description. When there is a fire breakout in the room the temperature increases. This ultra compact and low cost fire alarm senses fire breakout based on this fact. Transistor BC177 (Q1) is used as the fire sensor here. When...
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Rain alarm circuit

admin January 21, 2014 64 Comments
Description. Here is a simple rain alarm circuit that produces an audible alarm when ever rain falls. The rain detector circuit is based on two transistors (Q1 & Q2) and a NE555IC (IC1). The two transistors are wired as...
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Light to Frequency converter circuit

jacky February 28, 2011 1 Comment
A simple Light to Frequency Converter Introduction. Here is the circuit diagram of a effective light to frequency converter circuit that can be used for variety of applications such as light intensity measurement,fun etc. The circuit is based on...
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USB LED Lamp circuit.

admin February 23, 2011 19 Comments
USB Lamp Circuit Description. Here is a simple USB powered lamp that can be used to light your desktop during power failures. The circuit operates from the 5 Volt available from the USB port.The 5V from the USB port...
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Remote controlled switch circuit

admin November 15, 2011 49 Comments
Remote controlled switch for Appliance Description. Here is a versatile remote controlled  switch that can ON or OFF any appliance connected to it using a TV remote. IR remote sensor IC TSOP 1738 is used for receiving the signal....
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Simple Alarm circuit

admin February 23, 2011 1 Comment
Multi Tone Alarm Description This is a simple and easy to build multi tone alarm circuit that can be used in burglar alarms or sirens. The circuit is based on dual op amp MC1458 and  LM 380. The two...
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Sound Generator Circuit

admin February 23, 2011 No Comments
Simple Sound Generator Circuit Description This is a real scream generator circuit suitable for any purpose like alarm or car horn.The circuit is based on two transistors Q1 and Q2.When you press the switch S2 the siren starts up...
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Sensitive Intruder Alarm Circuit

admin November 18, 2011 67 Comments
Intruder Alarm Circuit Description Here is  the circuit diagram of an ultra sensitive intruder alarm. The shadow of an intruder passing few meters nearby the circuit is enough to trigger the alarm. Here IC2 uA 741 is wired as...
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Dual Tone Train Horn Circuit

jacky February 22, 2011 3 Comments
Description. A dual tone train horn simulator circuit can be made using two NE 555 timers connected in cascade.Here instead of using two NE 555 timers a single NE 556 timer is used which is a nothing but two...
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DoorBell circuit using UM 66 IC

admin April 27, 2011 29 Comments
Doorbell Circuit Description Here is a simple and easy to build doorbell circuit using IC UM 66.The  details of UM 66  is given in the older post “Melody Generator using UM 66″. This is a slight modification of that...
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