Hi,
I am using two serial in parallel out shift registers. I am using 2 555 timers to clock in the latch and clock. Data is supplied from my microcontroller.
It was working fine on day one, but today (day 2) the shift registers ONLY work if I touch them (which is probably not a good idea).
I have been sniffin around the circuit with a multimeter. I am using a 7805 voltage reg. to power both 555s and both 595s. ALL grounds are tied (ground from micro, ground from 7805, and ground from 12v DC [used for high power lights that 595s are controlling and also used as input to 7805]).
I mention all this because when I look at the voltage from the 7805, the input only reads around 1 volt and the output is even lower (0.5 volts).
Why would this be? I thought maybe using a second power source just for the regulator would solve the issue, but w/ a seperate 9 volt still the same issue (but everything WAS working w/ this configuration yesterday).
I am guessing the logic levels are too low for the 595, especially because output of the timers is even lower then their input voltage.
So, it DOES work when i touch them, but that is not really feasible. I didn't use a socket for them, so i can't pop in new chips.
Any suggestions, similar experiences? I am I just adding current by touching? If so how can I get more juice into/out of the 7805. It tried replacing the 7805 twice and still same result.
Best,
thanks for the patience,
Max
if i need to post a schematic thats fine...
I am using two serial in parallel out shift registers. I am using 2 555 timers to clock in the latch and clock. Data is supplied from my microcontroller.
It was working fine on day one, but today (day 2) the shift registers ONLY work if I touch them (which is probably not a good idea).
I have been sniffin around the circuit with a multimeter. I am using a 7805 voltage reg. to power both 555s and both 595s. ALL grounds are tied (ground from micro, ground from 7805, and ground from 12v DC [used for high power lights that 595s are controlling and also used as input to 7805]).
I mention all this because when I look at the voltage from the 7805, the input only reads around 1 volt and the output is even lower (0.5 volts).
Why would this be? I thought maybe using a second power source just for the regulator would solve the issue, but w/ a seperate 9 volt still the same issue (but everything WAS working w/ this configuration yesterday).
I am guessing the logic levels are too low for the 595, especially because output of the timers is even lower then their input voltage.
So, it DOES work when i touch them, but that is not really feasible. I didn't use a socket for them, so i can't pop in new chips.
Any suggestions, similar experiences? I am I just adding current by touching? If so how can I get more juice into/out of the 7805. It tried replacing the 7805 twice and still same result.
Best,
thanks for the patience,
Max
if i need to post a schematic thats fine...