Frequency meters are instruments that provide analog outputs as frequencies that vary as a function of the applied input. They display values on a dial, usually with a needle or moving pointer. Frequency meters measure repetitions per unit of time, usually per second, of a complete electromagnetic waveform. Most devices are deflection meters that balance two opposing forces and indicate changes in balance. There are two basic types of defection meters: moving-coil meters and ratio meters. Moving-coil meters are electrically resonant circuits that consist of two coils tuned to different frequencies and connected at right angles to one another. Frequencies in the middle of the range equalize the currents in the two coils and allow the needle or pointer to indicate the midpoint of the scale. Changes in frequency create an imbalance between these currents, causing both the coils and the needle or pointer to move. Ratio meters use two frequency inputs: a known standard and an unknown amount. Frequency ratios are often expressed as Lissajous figures, a common means of comparative frequency measurement in electronics.

Important specifications for frequency meters include units of measure, frequency accuracy, and estimated weight. Some devices provide fuse protection on functions. Others provide robust center-pole meter movements. Battery powered devices can be operated without plug-in power and are suitable for a variety of field applications. Temperature compensated devices include programming or electrical components designed to counteract known errors caused by temperature changes. Frequency meters with mirrored scales improve readability by enabling users to avoid parallax errors. Devices with a range switch allow users to select the range of units to measure. Frequency meters with overload protection and diode testing are also available. Some devices are handheld and portable. Others are designed for benchtop or shop floor use.

Frequency meters are instruments that provide analog outputs as frequencies that vary as a function of the applied input. They display values on a dial, usually with a needle or moving pointer. Frequency meters measure repetitions per unit of time, usually per second, of a complete electromagnetic waveform. Most devices are deflection meters that balance two opposing forces and indicate changes in balance. There are two basic types of defection meters: moving-coil meters and ratio meters. Moving-coil meters are electrically resonant circuits that consist of two coils tuned to different frequencies and connected at right angles to one another. Frequencies in the middle of the range equalize the currents in the two coils and allow the needle or pointer to indicate the midpoint of the scale. Changes in frequency create an imbalance between these currents, causing both the coils and the needle or pointer to move. Ratio meters use two frequency inputs: a known standard and an unknown amount. Frequency ratios are often expressed as Lissajous figures, a common means of comparative frequency measurement in electronics.

Important specifications for frequency meters include units of measure, frequency accuracy, and estimated weight. Some devices provide fuse protection on functions. Others provide robust center-pole meter movements. Battery powered devices can be operated without plug-in power and are suitable for a variety of field applications. Temperature compensated devices include programming or electrical components designed to counteract known errors caused by temperature changes. Frequency meters with mirrored scales improve readability by enabling users to avoid parallax errors. Devices with a range switch allow users to select the range of units to measure. Frequency meters with overload protection and diode testing are also available. Some devices are handheld and portable. Others are designed for benchtop or shop floor use.

Frequency meters are used in a variety of applications and industries. For example, some devices are used to monitor vibration levels from heavy equipment. Others are used to verify the frequency of RF signals independently of electronic circuitry which may be susceptible to interference from parasitic harmonics or cross modulation. Often, frequency meters that are used with RF signals provide a high degree of measurement accuracy and include calibration data.