Does anyone know how to supply eletricity to a component on an accurate scale?

... and its various applications - current mirror, Wien oscillator, Deboo integrator...

We have shared the belief that the balanced bridge circuit is omnipresent and can be seen in many applications. But entering, with a children curiosity:) more deeper and deeper into the essence of things, we finally arrived at the most fundamental questions, "What is a balanced bridge circuit? What are its unique properties? What and where is the 'bridge' there? What is its role?"

Thinking on these primary questions, I finally figured out that the simple basic idea of a balanced bridge circuit is to connect two equal voltage sources by a third, passive element. The voltage sources are grounded while the coupling element is "floating". So, the most elementary bridge circuit consists, all in all, of three elements - two grounded sources and one floating element. This element, "stretched" between the sources, is actually the "bridge" that connects them. Figuratively speaking, the floating element is the "bridge over the river"... and the two sources are the "banks of the river":)

In circuitry, it is inconvenient for us to use multiple voltage sources. So, we replace (implement) them by multiple voltage dividers (two resistors in series) supplied by only one single source. This yields the famous 4-resistor bridge circuit where a fifth element is connected between two equipotential points. The most interesting questions here are about the properties of this "bridge element".

It is placed at very special conditions - both the voltage across and the current through it are zero... but it can have any resistance - from zero to infinity. I.e., in the case of a well-balanced bridge circuit, whatever we connect between the two points (even to short or leave them unconnected), nothing will change... Or, if we connect some element... and then balance the circuit... we can remove the element... and nothing will happen...

After I directed the discussion towards more unusual perspectives on this legendary circuit, I propose to continue further below in this direction...