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555 for the HP-42S

By Ton van de Burgt

Several solver programs for handling a 555 timer.


Monostable operation



T= 1.1 x R x C [seconds]

Usage:



Start the solver and select “555M”

 

Fill in the known values and solve for the unknown value.


Astable operation

 

Oscillation frequency:
f = 1/T = 1 / 0.693 x C x (R1 + 2 x R2)

Usage:



Start the solver and select “555A”
 
Fill in the known values and solve for the unknown value.

Binary files for emulators:
Raw binary: 555a.raw  Binary for HP-42X: 555a.42x (HP-48) 555a49.42x (HP-49)
Raw binary: 555m.raw  Binary for HP-42X: 555m.42x (HP-48) 555m49.42x (HP-49)






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