Velleman K8000, Manual, Page: 9 / 16

9
An input attenuator of 10. This means that up to 50V may be connected to the
input, which is then reduced by a factor of 10. With the first values the input
impedance is 20kÙ. With the values in brackets the input impedance is 200kÙ.
With higher input voltages it is advisable to choose high values for the resis-
tors, otherwise resistors of a high power rating must be used for RA.
Att = 10
att = RB .
RA : 18K (180K) RA + RB
RB : 2K (20K)
CA : /
Conversion of current to voltage. In order to avoid interruptions, it is possible
for a variable current to be measured as the reference input value which is
used for current to voltage conversion. Here a variable current from 4 to 20 mA
is converted to a voltage of 0.8 to 4V.
4—20mA > 0,8—4V
RA : J
RB = 200 ohm
CA = /