Vibrating-reed Frequency Meter – Working – Construction – Range – Advantages – Disadvantages

Vibrating-reed Frequency Meter

vibrating-reed frequency meter is measuring instrument which is used to measure the frequency of various electric circuits. It consists of 7 vibrating reeds and each vibrating reed has a specific value. These reeds vibrate when this frequency meter is connected to supply for the measurement of frequency. A reed which vibrates more as compared to the other reeds, the more vibrating reed is considered as frequency reading of a supply or electric circuit.


This frequency meter consists of thin flat steel reeds which are arranged alongside and these reeds are near to the electromagnet. The electromagnet consists of a laminated armature and a winding connected with a resistance in series on it. This winding is connected to the AC supply whose frequency is to be measured. The metallic reeds are 4mm wide and 0.5 mm thick. These metallic reeds are arranged in a row and consist of flexible bases and these bases carry the armature of the electromagnet. These reeds are colored with white color. These reeds are arranged in ascending order of frequency on a scale.


These vibrating reed frequency meters consists of small readings from 47 Hz to 53 Hz and 57 Hz to 63 Hz.

Working of Vibrating-reed Frequency Meter

To measure the frequency of the circuit, it is compulsory to connect the frequency meter to a supply. The electromagnet is connected to the supply for which frequency is to be measured. The magnetism of the electromagnet alternates with the same frequency and the electro-magnet exerts the attracting force on each reed once every half cycle. All reeds start vibrating but the reed whose frequency is double, vibrates with maximum amplitude due to mechanical resonance. The vibration of the other reeds is so small and these are unobservable.


Its indications are independent.

Its readings are reliable.

These are cheap.


The reading is not be observed properly if the frequency difference is half cycle between the adjacent reeds.

These instruments are not accurate to provide the exact reading on its scale.

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