This page brings you to a channel recording (QuickTime format) of a phospholipid bilayer containg Gramicidin D. The fiugre below shows a snapshot of a computer screen to analyze the recording. There are clearly six different levels (on horizontal) visible, the lowest representing all channels closed, and each additional level the opening of a channel unit (= peptide dimer). Note that except for three periods of less than a second when all channels are closed, the membrane contains up to five active channel units that constantly open (up) and close (down). Also most channels have the same amplitude, one channel is clearly smaller, i.e., carries less current or transports fewer ions per unit time (upper left corner). This may be due to impurities in Gramicidin D preparation (Gramcidin peptide is a mixture of peptides A or D). 

The length of the trace shown here is 10.027 seconds and the amplitude of the whole window (vertical) is 13.65 pA). Thus a single channel measures 2.7 pA.