Ammeters

Problem Statement

• Replace 1K resistor in voltmeter as converted ammeter.
• Learn how to use circuit lab.
• Use circuit lab to find the resistors.

voltmeter,ammeter and schematic review

Demonstrate how voltmeter works: Open voltmeter check inside

• It is easy to solder on the resistor and put the meter back together.

• Figure out how to convert voltmeter to ammeter.
  • Here is a solution. Conversion of voltmeter to ammeter
  • Following this pdf instruction to find the resistor.

• Where to place the ammeter in the power supply?
• Figure out why need a shunt resistance.
• Figure out why change series connection to parallel connection

The Design Process

• Open up the voltmeter.
  • unscrew the front cover.

    

    This is the front view after I take off the front cover.

  • unscrew the back cover.

    

    This is the back nuts we need to unscrew them.

  • take out the inner part,then will see the resistance on back.

    

    Voltmeter inner part

    

    See voltmeter resistance on the back after take out inner part.

  • change voltmeter's resistance to a smaller shunt resistance.(1ohm or <1 ohm,need to confirm)
  • put shunt resistance in parallel connect.
    • Solution:replace 1ohm resistor with voltmeter's resistor.

Experiment prototypes and tests need for design

• We will test the ammeter and use it in the power supply.