I'm trying to get a steady 5 volts from a 6 volt battery. The 5v will power a circuit that draws a variable amount of current (between 70 and 100 ma). I've used LM7805 in the past but I know they need more then just one volt difference.
I do have a 1/2watt 5 volt zener I could use but I can't seem to get it to work properly. Would it be wired in series?
Or should I just use a dropping resistor, even though the current draw changes?
Thanks
You could use the zener. The series resistor feeds the zener and you tap your 5 volts from the zener. The series resistor needs to allow for all the current that you need and the zener needs to be able to handle what you take from it. PS: The resistor sees both currents, the zener current and the load. Also there are low overhead VRs. Can you look up any info on this?
Tom
Do you need exactly 5V or is 5.4V Ok for you? The simplest way to get 5.4V is using a 1N4001 connected as below:
[Battery +]--------->|---------[Load]--------[Battery -] 1N4001If you must use 5V zener connect it this way:
[Battery +]---------[ 6.8 ohm]---------+-----------+ | | K 5v zener [RL] A | | | [Battery -]----------------------------+-----------+Allen
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