Table of Contents
Signals are voltages that are not really meant to provide power.
Trimpots (trimmer potentiometers) use a sliding resistance based voltage divider to output any voltage between what is across it’s end terminals.
This circuit has +10V on one side of the trimpot, and ground (0V) on the other side of the trimpot. The trimpot can be turned to output any voltage between 0V and +10V.
Since it resistance based though, any current it output goes through resistance. Therefore, current demands will greatly change the voltage being output.
An op amp (operational amplifier) follower non inverting (+) input, just looks at the trimpots output voltage as a signal, and the amplifier follower outputs that same voltage.
Negative feed back is wiring the output to the inverting input (-). For the follower, you make that a direct connection. The op amp output (instantly) goes up or down until the voltage at – is the same as +.
The LM358 is a single supply op amp. Which means that it can output the negative supply (oV ground in this case), but falls a bit short of the positive supply.
Op amps are much better at providing current/power than most potentiometers. Therefore, you can easily set a voltage you want with a trimpot. Maintaining that voltage across a load, as long as the power demands is within the op amp’s limits, instead of the trimpot’s.
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