Not to be confused with the Casio Micro-Mini Calculator that is used by Egon in the scene Fixer-Upper.
A PC-4 Calculator (also known as the Pocket Computer) was utilized by Egon Spengler while he worked in the University's Paranormal Studies Laboratory.
History
After their encounter with the Library ghost at the New York City Public Library, the Ghostbusters returned to Columbia University. Egon used the PC-4 to make some calculations with data collected on the P.K.E. Meter. The computations confirmed that a ghost could be captured and held in storage indefinitely, assuming the ionization rate remained constant.
Appearances
Gallery
Egon uses data to confirm ghostbusting theory
Will you stop doing that?!
As seen on Egon in they Ad that Dana viewed