Labo Élec

electrical lab simulator
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Exercise from the chapter "Measurement & instruments"

Upstream or downstream connection

Level 3 of 5 · 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-

Workbench

Circuit diagram CEI 60617

How does it work?

The perfboard: each big hole is a circuit node. You push a single leg of a component (resistor, lamp...) into it. The 4 small holes around it are connected to it: that is where chips and leads plug in.

  1. Drag a component onto the board: it snaps onto the grid. R rotates it.
  2. To join neighbouring big holes, click Jumper chip in the palette (or C) then drag on the board: a line of chips is laid at once. Bridged holes become a single node.
  3. For long links and for the power supply (placed next to the board), drag a lead from one big hole to another (or to a terminal).
  4. As soon as a loop is closed, the circuit is solved in real time (Ohm + Kirchhoff) and the diagram follows.
  5. Zoom with the wheel (or + / −, two-finger pinch); drag the background to pan, 0 fits the board. The + buttons around the board add a row or a column.

Del delete · R rotate · C chip brush · Esc cancel · wheel zoom · drag the background to pan

Confirmer

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