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Solved exercise · level 3 of 5

Upstream or downstream connection

Skills: Know

Statement

To measure a large resistance with a voltmeter and an ammeter, the preferred connection is...

  1. Upstream (the voltmeter spans the ammeter)
  2. Downstream (the voltmeter is directly across the resistor)
  3. Both are equivalent
  4. Neither: an ohmmeter is needed
2 hints from Bastaya available in the lab
Solution

Large R: the drop in the ammeter (small r_A) is negligible against U_R, but the current shunted by the voltmeter is not → upstream connection.

Course sheet of the chapter : Measurement & instruments

This chapter is covered by the paths: General electricity, Measurement prep

Other exercises of the chapter

Simulated time00:00:00
Q = I·t-
W = P·t-

Circuit diagram CEI 60617

How does it work?

Each big hole is a circuit node: you push one leg of a component into it. The 4 small holes around it are connected to it: chips and leads plug in there.

  1. Place a component Drag it from the palette: it snaps onto the grid. R rotates it.
  2. Bridge neighbouring holes Pick the jumper chip (or C) and drag on the board: bridged holes become a single node.
  3. Draw a lead For long links and the power supply: from one big hole to another, or to a terminal.
  4. Close the loop The circuit is solved live (Ohm, Kirchhoff) and the diagram follows.

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