I want to charge my 9V NiMH cell with a LM7809. The problem is that I want to limit the current output to 20mA or 30mA. How can I limit the current output from that voltage regulator with simple components? What other components do I need? The input voltage to the LM7809 will be from a 12V source.
I know that this is not the best method to charge NiMH cells and that negative delta V along with temperature monitoring is required but what I'm building is a simple charger to be used in case of a one time emergency situation and I will stop charging it after a specific amount of time like 12 hours.