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Browsing Archive: August, 2011

FM receiver circuit

Posted by demysteryboy Inusah on Sunday, August 21, 2011,
CXA1019 FM receiver circuit

A high quality FM receiver circuit based on CXA1019 IC is shown here. CXA1019 is a bipolar silicon monolithic FM/AM radio receiver IC from Sony. Built in circuitries inside the CXA1019 include RF amplifier, mixe...


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Door bell circuit using NE555

Posted by demysteryboy Inusah on Sunday, August 21, 2011,
Door bell circuit using NE555

Description.

The main part of this doorbell circuit are two NE555 timer ICs.When some one presses switch S1 momentarily ,the loud speaker sounds a bell tone as long as the time period of the monostable multivibrator built around IC1.

When the switch S1 pressed, IC1 is triggered at its pin 2 and output pin 3 goes high for a time period previously set by the values of POT R4 and POT R5.When the output ofIC1 goes high it resets IC2 and it starts to oscillate to m...


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Temperature controlled LEDs

Posted by demysteryboy Inusah on Sunday, August 21, 2011,
Temperature controlled LEDs

Description.
The circuit is nothing but two LEDs (D1 and D2), whose status are controlled by the temperature of the surroundings. The famous IC LM35 is used as the temperature sensor here. Output of LM35 increases by 10mV per degree rise in temperature. Output of LM35 is connected to the non inverting input of the opamp CA3130.The inverting input of the same opamp can be given with the required reference voltage using POT R2. If the reference voltage is 0.8V, then...


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