The fuctionality of the three lamps can be changed from series to parallel by simply changing the source polarity of the circuit. A dual source was used to simply the type of switch necessay to change the polarity and allow for different source voltages to be used for tbe series and parallel fuctionalities. Also optional resistors in series with the source were added to allow control of the current in the two fuctionalities since the lamps tend to be too dim in series and/or too bright in parallel with the same voltage. The SPST switches in series with each lamp allow the verification of the functionality of the three lamps in the circuit as being either in series or in parallel.
