digital meter - buzzer or diode output for continuity testing

Discussion in 'The Projects Forum' started by Ken.W, Mar 30, 2015.

  1. Ken.W

    Thread Starter New Member

    Mar 30, 2015
    Hi Team

    First thread so be gentle.

    Had need the other week to get the continuity tester out for a bathroom Shaver light pull switch not latching.
    Anyway the battery in the MM was flat (or almost) and the buzzer tone on continuity (200ohm position) was so faint as to be non existant. - Hunting round for a 9v battery - made little difference to the sound.
    (I have just reached that senior citizen age for Bus Pass and possibly going a little deaf to some frequencies)

    My thoughts turned to :- what if instead of a buzzer on my meter it had a LED for an output. So the question is How to replace buzzer with LED. on Continuity.

    I happened to have one (from an old cordless drill charger) - but just adding it in parallel with the buzzer, just kept the led on all the time as you turned the selector switch. Also with buzzer removed.

    I don't want any thing fancy - Like transistors-oscillators etc - just led with a ballast resistor from MM 9v battery, and able to fit inside MM.

    MM is Powercraft M92A about 6-7 years old, replacing an old RS analogue meter.



    PS Of course my MM might just be (cream cracker'd) but seams to work, but it the only one I have so unable to test it.