A method and apparatus for providing welding-type power includes a source of welding-type power and a controller. The RFID interrogator also comprises a bypass path to direct received signals around the amplifier so that the amplifier does no block the reception of signals received from an RFID tag. Preferably the magnetic bubble is confined in an island of magnetic material, preferably of maximum dimension less than 1 \u03bcm. The internal ribs together define a plurality of apertures and an elongated passage that extends the length of the elongated body. The invention uses two or three membrane separation steps, optionally in conjunction with coolingcondensation under pressure, to yield a lighter, sweeter product natural gas stream, andor a carbon dioxide stream of reinjection quality andor a natural gas liquids stream. The conductive line is electrically coupled to a test portion of the same or, alternately, of a different metal layer.