problem in the power consumption of cmos ics

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hossam abdo

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hey all

i made a logic circuit contain
cmos 4011,4071,4009,4010 ics
3 transistors bd139
buzzer ans 2 motors 1.5 v (motors which in toys)

and the battery is 9v across regulation with 5v

the problem : when i running the circuit , the power consumption of the battery is very high
and the battery is down from 9v to 7 in 2 second after running the circuit

how to solve this problem and what is the source of the problem?

thanks in advance
 

Too high power consumption could have several reasons. What comes to my mind is that CMOS logic does not like slow switching signals on the inputs. It causes both transitors to be on at the same time. If this is the case schmitt trigger gates could be use. Noise or long lines could be another problem. If there is a high peak current demand, some batteries can't supply this and the voltage goes down(internal resitor). Buffer capacitors might help here.

Good luch with the trouble shooting.
 

hossam abdo said:
how to solve this problem and what is the source of the problem?
Click to expand...
Exchange: determine source of problem -> solution.

You'll have to measure where that battery power goes to, and that should make it clear what the problem is. I'd suspect those motors, and 2) if that 9V battery is of the type most people think about when they think of a 9V battery, well: that type is pretty weak, no good at higher-current tasks like toy motors. Do you know what was used to power those motors previously?

Also a schematic & perhaps a picture of the battery / motors you're using would help.
 

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