hi i have a MCU circuit board powered up as follows:
Transformer (9VA) ====>7805 Voltage Regulator====>PIC16F876A
(Board maximum current requirement=0.45A so transformer ratings are fine)
Is it possible that due to poor regulation of most common transformers, that a sudden current draw (say a relay gets activated and draws current for the coil) would result in unstability of the transformer? I say unstability because each time i turn on the relay, my PIC will reset. (My PIC MCLR is tied to Vcc via a pull up resistor).
I am using an NPN transistor switching circuit. I am quite certain its the relay drawing the sudden current that is the problem. If I disconnect the relay, (an open circuit between collector of transistor and Vcc) and I drive the transistor base (turn on the relay), the system remains stable only until I connect the relay back again and the system resets.
So once again, could it be due to the transformer problem? When I power my circuit via a power supply bench, none of the sort happens..
Hope to hear from you experts..
Thanks!
Transformer (9VA) ====>7805 Voltage Regulator====>PIC16F876A
(Board maximum current requirement=0.45A so transformer ratings are fine)
Is it possible that due to poor regulation of most common transformers, that a sudden current draw (say a relay gets activated and draws current for the coil) would result in unstability of the transformer? I say unstability because each time i turn on the relay, my PIC will reset. (My PIC MCLR is tied to Vcc via a pull up resistor).
I am using an NPN transistor switching circuit. I am quite certain its the relay drawing the sudden current that is the problem. If I disconnect the relay, (an open circuit between collector of transistor and Vcc) and I drive the transistor base (turn on the relay), the system remains stable only until I connect the relay back again and the system resets.
So once again, could it be due to the transformer problem? When I power my circuit via a power supply bench, none of the sort happens..
Hope to hear from you experts..
Thanks!