The RCBS Powder Trickler is a handy gadget that works very well with beam scales as the result of minute powder grains added will move the indicator.
Digitals take "their own time" (a few seconds) in deciding and displaying a charge that is thrown close to xx.x5 grains (EX: thrown = 43.3456 grains; value of display=43.3 grains). Trickling a "few kernals/flakes/balls" of powder in the digital scale's pan may, or may not
, move the digital dial, in the way it does on a beam scale.
[The] Scale is based around a Strain Gage Load Cell. This is a mature technology that is used in all but the most expensive electronic laboratory analytical balances. The load cell is energized with an electrical current. As you add weight it bends very slightly, a few thousandths of an inch at the most. This tiny bend changes the electrical characteristics of the strain gage producing a very small change in its output. We amplify this signal up to a measurable level then convert it from an analog to digital value that the computer inside your scale can read and convert to a weight.
If the computer displayed the actual readings it was receiving from the load cell you would find the scale all but unusable. There are two reasons for this; first of all, because of the speed that this electronic stuff whirls around, the scale picks up every little vibration and puff of wind in the room and instantly amplifies it. Secondly, in the great scheme of things, a tenth of a grain, one seventy thousandth of a pound, is a real small thing to pin down and measure.
Digitals are affected by wind, temperature, vibration, close proximity florescent lighting (Electro-motive Force; EMF), magnets, etc. The load cell, as noted above, is extremely sensitive and can easily be destroyed (dropped, overloaded, stretched, burned [power overload], etc.).
Through all of this, digitals are VERY FAST, VERY ACCURATE, and reloading is well served through their use.