I think those 1K resistors are overloading you PIC. I would suggest using ULN2003 to drive the solenoids.
hmmm even if its only connected to the base of the transistors?? You mean we will replace thos transistors with ULN2003?? Im looking at its Data sheet right now...
Uhm I hope youll reply again hehe.. tahnx
to the original poster:
pag gumawa kayo ng ckt, dapat step-by-step.. power supply first then PIC.... sa tingin ko naka reverse yung connection sa PIC(umiinit lang yan pag neka reverse connection)...
yupp thats an SOP(standard operational procedure) for us electronic builders.. I didnt bypassed that step.. In fact lahat ng testing bago ikabit to the supply ginawa namin.. At saka un sa supply naman naghanap din kami at inayus ng maigi kaya napunta kami sa pag gamit ng LM340 Voltage regulator...
Ung regulator nakumpirma namin na hindi naman baliktad ang
Each I/O of the PIC can source or sink 25mA max.
1K load in-front of a transistor is I = (5-0.7)/1K = 4.3/1000 = 4.3mA only.
Nevertheless ULN2003 is very good for driving multiple common loads.
Regarding the heating problem, check for LM340 pin inversion.
Also, I don't see any capacitors on the regulator.
A capacitor at its input is *NEEDED* if it is far from the supply.
A capacitor also on the output is needed for transient.
Its datasheet should give the right values for these caps.
Yes before we connect the solenoids to the PIC we tested each solenoid using the LM340
the regulator did not heat up. Plus we didnt use the capacitors you are referring too.
Kaya sa previous posts ko dito sabi ko kanina bili muna kami ng Capacitor sa labas.
Ngayun nakabit n namin ung capacitors na nsa input and output ng Regulator.
Pero they both, PIC and Regulator, still heated up..