How control a Relay with PIC

Hi

I want control a relay with PIC
I need some eschematic for this

Thank you

Have look at the previously discussed topic

not to be rude, but there are billions of circuits available on the internet that does that. Maybe you could look in google first?


ASIC

OK
sorry for my question, but I had contribute to this forum board too.

Bye

For small current relays and cheap circuit I use transistors to drive the relay from the PIC ports.
A NPN general transistor (BC547) can be used to drive up to 100mA coils. More than this you can use a darlington transistor or use a MOSFET (drivered by bipolar transistor).
Vcc
___!___
! !
_ !
1N4007 Λ Rly coil
!______!
!
!
C
PIC port >--Resistor----B NPN transistor
E
!
GND

Just remember to use 1N4007 diodes to Back Voltage generated by the coil.
The relay is activated by high logic level (4.7V in the PICs). The resistor is calculated:

R = (4.7V - Vbe)/Ib

Ib = Ic / transistor beta (Ib cannot be greater than 25mA)
Ic = current in the coil
Vcc must be at less the coil voltage + Vce saturation


The PIC I/O ports can source or drain up to 25 mA, so they can be connected directly to small reed relays (use the diodes reversed).

rkodaira, you should use tag "code" to preserve formatting of your picture, otherwise it is like mess.

As to relay control, small example with double-transistor is attached.

For many relay outputs I would suggest to use ULN2003 driver - it has Darlinghton and protection diode inside for 7 channels.