Lab 2 issues with small resistors

Henrik reported that there are some issues when trying to operate the Opamps as inverting amplifiers with small resistors, i.e. smaller than 200 Ohm and according to the specification in the task that would require 100mA when the input is at 10V. If you see this happen please try the following: reduce the input swing from +/-10V to +/- 3V (but leave the power supply at +/-10V!) and dimension the resistors still for a gain of -1 but for a current at 10V input of 10mA or lower if necessary. See if that helps and be aware of the impact on your transresistance amplifier in task 2 this might have.

Also the text does not specify what supply you should use for the MC14007 chip: please use 0V and 10V and swing the inputs (Vgs and Vds) from 0V to 10V, or maybe just from 0V to 3V if you have reason to suspect that the output from your transresistance amplifier becomes unreliable/wrong for too high currents. But try to adapt the resistor in the transresistance amplifier to get good readings in the relevant current range!

 

Publisert 28. sep. 2018 16:39 - Sist endret 28. sep. 2018 16:39