Integrator
Integrators are the essential building blocks of analog computers. They perform integration in time, as in c = integral_0^t integrand(t') dt'
. The Analog Thing features five integrators. This allows computing five integrals in a program.
Electronic analog computers typically perform integration by charging and discharging capacitors. The key difference between an integrator and a summer is the capacity in the feedback channel instead of a simple resistance. Accordingly, all integrators are also summing their inputs. For more details, please refer to Analog computing literature.
Basic Usage of an Integrator on The Analog Thing
- Circles represent inputs, triangles represent outputs
- Analog integrators sum their inputs. That is, if you have a sum under your integral, you can save a single summer before the integrator. Otherwise, just put your integrand into the upper left input labeled with
1
. - There are two output slots. Just use one of them as you like.
- The
IC
slot stands for initial conditions. It is an input where you have to provide suitable initial conditions. As shorthands,-1
and+1
are right to the hand. If this slot is left empty,0
is taken as initial condition. - Beginners may ignore the slots
SJ
andSLOW
.
Attention: Make sure the sum of your inputs does not exceed the machine unit (±10V), otherwise an overload will occur (indicated by the OL LED) . See Logic levels for details.
Extended Usage of an Integrator
Changing the integration speed
You can change the integration time scale factor k0
of a particular integrator by connecting SLOW
to OUT
. This effectively decreases the k0
by factor 100. The circuit on the right was taken from File:Anathing v1.0 base 3.pdf.
Making use of the Summing junction
See also XIR.