Joe McGivern
New Member
Voltage Regulation post.
The charging voltage for my PDA (hp iPac) is 5 volts DC. I've got an adaptor (with centre +ve) whereby I can connect it to a 230 volt ac charger or to a USB port on my laptop.
I connected a 12v dc supply from my car cigarette lighter to the input to an L4940V5 voltage regulator and fitted a smoothing capacitor across the output. On no load the voltage is stable and is 4.98 volts.
I connected the output to a suitable low volt plug (4mm OD and 1.7mm ID) hoping to charge the battery in my PDA from my car socket.
The regulator very quickly overheats when I connect the regulator to my PDA.
Can anyone advise me what the problem is likely to be?
I Tried to put a small explanatory sketch in with the post but the file size is too big.
The charging voltage for my PDA (hp iPac) is 5 volts DC. I've got an adaptor (with centre +ve) whereby I can connect it to a 230 volt ac charger or to a USB port on my laptop.
I connected a 12v dc supply from my car cigarette lighter to the input to an L4940V5 voltage regulator and fitted a smoothing capacitor across the output. On no load the voltage is stable and is 4.98 volts.
I connected the output to a suitable low volt plug (4mm OD and 1.7mm ID) hoping to charge the battery in my PDA from my car socket.
The regulator very quickly overheats when I connect the regulator to my PDA.
Can anyone advise me what the problem is likely to be?
I Tried to put a small explanatory sketch in with the post but the file size is too big.