 There is no need for a fixture and hence the fixed costs are much lower.The CAM system "instructs" the electrical tester to apply a voltage to each contact point as required and to check that this voltage appears on the appropriate contact points and only on these.In assembly the bare board is populated (or "stuffed") with electronic components to form a functional "printed circuit assembly" (PCA), sometimes called a "printed circuit board assembly" (PCBA).