Grid dip oscillator also called grid dip meter, dip meter, dipmeter, or just dipper, is a measuring instrument

Measuring instrument

In the physical sciences, quality assurance, and engineering, measurement is the activity of obtaining and comparing physical quantities of real-world objects and events. Established standard objects and events are used as units, and the process of measurement gives a number relating the item...

 to measure resonant frequency of radio frequency

Radio frequency

Radio frequency is a rate of oscillation in the range of about 3 kHz to 300 GHz, which corresponds to the frequency of radio waves, and the alternating currents which carry radio signals...

 circuits. It measures the amount of absorption of a high frequency

High frequency

High frequency radio frequencies are between 3 and 30 MHz. Also known as the decameter band or decameter wave as the wavelengths range from one to ten decameters . Frequencies immediately below HF are denoted Medium-frequency , and the next higher frequencies are known as Very high frequency...

 inductively coupled magnetic field by nearby objects. It is an oscillator

Electronic oscillator

An electronic oscillator is an electronic circuit that produces a repetitive electronic signal, often a sine wave or a square wave. They are widely used in innumerable electronic devices...

 whose output energy changes in the vicinity of a resonant circuit which is tuned to the frequency the oscillator generates; somewhat similar to an acoustic tone becoming louder when generated in the vicinity of a resonant cavity or a string tuned to the same frequency. At the heart of the instrument is a tunable LC circuit

LC circuit

An LC circuit, also called a resonant circuit or tuned circuit, consists of an inductor, represented by the letter L, and a capacitor, represented by the letter C...

 with a coil

Coil

A coil is a series of loops. A coiled coil is a structure in which the coil itself is in turn also looping.-Electromagnetic coils:An electromagnetic coil is formed when a conductor is wound around a core or form to create an inductor or electromagnet...

 that serves as a loose inductive coupling to the measured LC resonant circuit. Resonance is indicated by a dip in the meter indicator on the device, usually based on a microammeter.

History

Grid dip oscillators were first developed in the 1920s, and were built with vacuum tube

Vacuum tube

In electronics, a vacuum tube, electron tube , or thermionic valve , reduced to simply "tube" or "valve" in everyday parlance, is a device that relies on the flow of electric current through a vacuum...

s. The devices measured the value of the tube's grid

Control grid

The control grid is an electrode used in thermionic valves used to modulate the flow of electrons in the cathode to anode or plate circuit.- Operation :...

 current. Modern grid dip oscillators are solid-state

Solid state (electronics)

Solid-state electronics are those circuits or devices built entirely from solid materials and in which the electrons, or other charge carriers, are confined entirely within the solid material...

 devices and are more versatile. Solid-state versions of the grid dip oscillator are sometimes called gate dip oscillators or emitter dip oscillators in reference to the parts of the semiconductor

Semiconductor

A semiconductor is a material with electrical conductivity due to electron flow intermediate in magnitude between that of a conductor and an insulator. This means a conductivity roughly in the range of 103 to 10−8 siemens per centimeter...

 whose current is being measured instead of the grid current on a vacuum tube.

Applications

Grid dip oscillators have been widely used by amateur radio operator

Amateur radio operator

An amateur radio operator is an individual who typically uses equipment at an amateur radio station to engage in two-way personal communications with other similar individuals on radio frequencies assigned to the amateur radio service. Amateur radio operators have been granted an amateur radio...

s for measuring the properties of resonant circuits, filters, and antennas

Antenna (radio)

An antenna is an electrical device which converts electric currents into radio waves, and vice versa. It is usually used with a radio transmitter or radio receiver...

.

External links

• Grid Dip Meters gallery