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seven segment display with uln
I'm using ATmega16
the pull ups are useless.. ignore them ^^
I'm using the same circuit as yours, minus the R1 and the pull up resistors Rb..
It's working but the 7805 is very hot when all the 6 segments are ON..
7805 current boost transistor
i don't use heat sink..
coz i want it to be small..
if i use 2 7805, then one of the 7805 which drive the seven segments will the hot right?
BTW what is current booster..?
thx
schematic for seven segment
hi..
I'm using common anode seven segment..
the circuit is similar to ctownsend schematic..
but the problem is my 7805 become very hot when the seven segment ON..
what should i do?
thx
current booster 7805
Hi guys..
I'm designing a safety deposit box with 6 seven segment as display..
I drive the seven segments using pnp transistor.. but the 7805 become very hot when the seven segments are ON..
can I use the 12v power supply to supply the seven segments?
what should I use...
Hi all.. I'm designing a Safe deposit box..
It use motor to open and close the box..
but i want to know if the door is blocked when closing/opening..
I realize that the current needed for the motor will increase if it's blocked..
I'm using ATmega ADC, but it need voltage input..
so i need a...
atmega low-ohmic shunt
Hi all.. I'm designing a Safe deposit box..
It use motor to open and close the box..
but i want to know if the door is blocked when closing/opening..
I realize that the current needed for the motor will increase if it's blocked..
I'm using ATmega ADC, but it need...
Re: need help with RS-485
thx for the ideas.. i'll try it tonight.. thx all
Added after 1 hours 37 minutes:
Hi all.. I discover that the power supply is not the problem coz i just tried it using laboratory power supply and it still doesn't work with long cable.
my design is like this:
PC...
need help with RS-485
I believe there's no short circuit...
I'm using external power supply for both the converter and the 485, connected to 7805..
and i'm using 9600 bps baud rate..
When the device transmit data to the converter (PC) there's no problem.. but when the PC transmit data, the...
Re: need help with RS-485
no problem with the supply.. coz it works for 10-20 m cable but not in even 30 m cable!!
i don't know what's wrong.. shouldn't 485 support up to 1000m++?
rs485 data bounce
Hi all..
I design a network using 485 protocol.
it connected to computer using rs485 to rs232 converter..
at first i use short cable (10m) with termination resistor 120 ohm.. but it didn't work.. when i didn't use the termination resistor it work well.
but when i change to...
Hi all..
I intend to make multiple security doors (maybe 4) with keypad or rfid that all connected to a server pc so the pc can monitor and control the doors.
I think I should use RS-232 to RS-485 converter then connect all the doors to the pc via 485 and for the pc i use borland delphi to...
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