# lights

Discussion in 'Electronic Basics' started by Flava, Jan 8, 2005.

1. ### FlavaGuest

If ive got two small lights, both 1.5v each, does that mean i need 3v to
power them both? Are there different ways I can hook them up if i have more
lights?

2. ### John PopelishGuest

If by "lights" you mean incandescent lamps, you can connect them in
parallel to a 1.5 volt source (like a D cell). In this mode, there is
no particular reason that all lamps must pass similar currents, only
that they all require the same voltage.

If they all use the same amount of current they can also be
connected in a series string and the string connected across a voltage
supply that is 1.5 volts times the number of lamps. In this mode,
there is no particular need for them to each require the same
voltage. E.g. 4 1.5 volt lamps in series would need a 6 volt supply
but would operate correctly only if they were all designed to operate
at the same current.

The rule is that voltages in series add (in this case, the voltage
drops of each of the lamps). Currents in parallel add, so connecting
the lamps in parallel does not change the voltage requirement, but the
current the supply must provide is the sum of each of the lamp
currents.