Im designing a board with a pic microcontroller. In the past i have used darlington arrays, which can be driven directly from the microcontroller. I now need to use a single npn transistor as a switch. In most applications that i have seen there is a biasing resistor being used.
I am wondering if i can bias the transistor without using a resistor to drive it directly into saturation. With a maximum output of 20ma from the ucontroller this seems resonable, but i am not sure.
If this does not pose a problem to the transistor or microcontroller can i use this practice in general, even when there is a non regulated amount of current that can flow into the base, where i dont care what the collector current will be and only care that the transistor is in saturation?
In general i would like to know what my limitations are and when i may end up damaging the transistor??
Thanks for your input.
I am wondering if i can bias the transistor without using a resistor to drive it directly into saturation. With a maximum output of 20ma from the ucontroller this seems resonable, but i am not sure.
If this does not pose a problem to the transistor or microcontroller can i use this practice in general, even when there is a non regulated amount of current that can flow into the base, where i dont care what the collector current will be and only care that the transistor is in saturation?
In general i would like to know what my limitations are and when i may end up damaging the transistor??
Thanks for your input.