I'm trying to hook up some DC lights from a car battery. Both sets have 20 light bulbs, the first set runs of two C batterys 3 volts the second set runs off of 4 dub A batterys total of 6 volts Both sets are in parallel with a extrea ground running from the farthest end . Voltage Drop (I think) I'v been pulling my hair out trying to measure the current in the circuits and resistance in the bulbs,I keep getting different measurements. i not sure what scaile i'm on, or if i measuring ohm's, kilo ohm;s mega ohm's, or if i'm measureing the current in the right spot with the third ground, Can someone straighten me out.
Thanks Mark
Can you measure amps directly with your multimeter? You'll have to break the circuit to do so. A regular 100 bulb mini christmas light string uses about .2 amps at 120 volts so at 12 volts it would use 2amps. That's about 6ohms for the entire circuit. You should be on the ohm's scale. If you're going to wire them to a car battery you have to wire some in parallel or series to get the same wattage through the bulbs without burning them.
How many wires does each string have? Are you sure they are all in parallel? That would mean that you could take any one bulb out and the rest would still be lit.
-------------
Poly Dollies
Reberto
thamks for making me take the string apart, what I have found Is from 6volt string I have 5 string of 4 bulbs in Paralle, A total of 5 string 20 Bulbs total 4 blubs conceted to 4 blubs ect. I have 5 Rows of 4 blubs, How do I test this Circuit, I remember a Formula for like resisent in parllel but i can't find it , I don't think i'd know what to do with it anyway. Thank for taking the time Makm