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JK flip flop circuit problem

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Jasmeet Kaur

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I am using 74LS112N JK flip flop, and i'm giving 5 volts to the circuit using 7805, which becomes extremely hot, when the circuit works. I have connected 0(GND) to CLR, K=0,J=1 CLK=1, PRcomplement=1, what could be the problem? When I give an i/p of 12V, the i/p that reaches 7805 is just 3.8, and also it becomes unbearably hot..
 

chuckey

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1. Ensure that without the 74112, the 7805 produces ++++5V, note the polarity.
2. Ensure that the Q and not Q pins of the 74112 are not connected to anything.
3. Re-connect the 74112 and if the 7805 is only producing 3.8V and getting hot, unplug the 74112 and throw it away. its faulty.
Frank
 

yadavvlsi

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Your 74112 is faulty. Voltage is dropping down to 3.8V due short circuit inside 74112. Try with another 74112. Also don't give 12V input to 7805. keep it less than 9V. Giving 12V also cause heating of 7805.
 

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