Author: Manikandan KJ ©kjmindia.in Here is another audio annunciator used in factories, industries, hospitals, auditoriums, theatres, etc. to indicate the power failure and resumption. The circuit will give a long beep on power resumption and an intermittent beep when power fails. The power failure alarm circuit that I posted earlier will activate the alarm (continuous tone) only for a few …
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Author: Manikandan K J This circuit produces an audible alarm when the water level in a rain or water tank rises above a preset level and overflows. It will sound an alarm whenever the water level reaches the top position in the overhead tank, thus it alerts one to turn off the motor to prevent water wastage. The purpose of …
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Author: Manikandan K J This is a very simple circuit built using only a few components to detect ac mains power failure and its resumption. The heart of the circuit is the most popular timer Ic 555 which is wired as monostable multivibrator. Battery, Diode D1, D2, Led L2 and resistor R2 are wired in such a way that the …
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Authоr: Prаdеер G Source:EFY Thіѕ project саn еffесtіvеlу be used as a tеmреrаturе-ѕеnѕіng fіrе alarm. Here, an NTC thеrmіѕtоr іѕ used аѕ the temperature ѕеnѕоr. Rеѕіѕtаnсе of thе NTC thеrmіѕtоr dесrеаѕеѕ wіth аn іnсrеаѕе in temperature. Parts Lіѕt: Semiconductors:IC1,IC2-NE555 TImеrT1-BC547 NPN TrаnѕіѕtоrLED1-5mm Rеѕіѕtоrѕ(1/4w,+/-саrbоn):R1- 22KR2- 4.7KR3,R6- 1KR4,R7- 56KR5- 680ER8- 10EVR1- 100K Pot Capacitors:C1,C6- 100uF,25VC2- 2.2uF,25VC3,C5- 0.01uF,сеrаmіс discC4- 0.047uF, сеrаmіс disc …
Read More »The burglar alarm circuit shown here sounds an alarm when the wire loop is broken.The system is implemented by installing a sensing loop, which is basically a thin copper wire. This way, the loop is both invisible and brittle enough to break easily and initiate the alarm mechanism.At the time of an intrusion, the loop breaks and this causes the …
Read More »Author: Manikandan K J Components Required:Resistors (All 1/4W)R1 – R6 – 1MR7 – R12 – 220KR13 – R17 – 1KR18 – 3.3KR19 – 1MR20 – 100K (Preset)R21 – 1KR22 – 1.5K Capacitors:104(0.1uF) – Ceramic Disc – 1 no.100uF,25V – 1 no.470uF,40V – 1 no. IC:U1- CD4049 (with Base)U2-555(with Base) Diodes:D1 – LEDD2 & D3- IN4148DB1- W04 (Bridge Rectifier) Transistor:S8550 PNP Relimate Connector:Sensor – 8 …
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