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Cantenna dummy load suitable up to 30 MHz and up to 1 kW
Cantenna dummy load suitable up to 30 MHz and up to 1 kW

A dummy load is a device used to simulate an electrical load, usually for testing purposes. A "cantenna" is also a brand name for a Dummy load. A cantenna is a directional Waveguide antenna for long-range

Contents

Radio

In radio this device is also known as a dummy antenna or a radio frequency termination. Radio frequency ( RF) is a Frequency or rate of Oscillation within the range of about 3 Hz to 300 GHz It is a device used in place of an antenna to aid in testing a radio transmitter. An antenna is a Transducer designed to transmit or Receive electromagnetic waves In other words antennas convert electromagnetic waves into For biologic transmitters see Transmitter substance. A transmitter is an electronic device which usually with the aid of an antenna It is substituted for the antenna while adjusting the transmitter, so that the transmitter does not interfere with other radio transmitters during the adjustments. [1] If a transmitter is tested without a load, such as an antenna or a dummy load, the transmitter could be damaged. Also, if a transmitter is adjusted without a load, it will operate differently than with the load, and the adjustments may be incorrect.

The dummy load ordinarily should be a pure resistance; the amount of resistance should be the same as the impedance of the antenna or transmission line that is used with the transmitter (usually 50 Ω or 75 Ω). Electrical resistance is a ratio of the degree to which an object opposes an Electric current through it measured in Ohms Its reciprocal quantity is Electrical impedance, or simply impedance, describes a measure of opposition to a sinusoidal Alternating current (AC [2] The radio energy that is absorbed by the dummy load is converted to heat. A dummy load must be chosen or designed to tolerate the amount of power that can be delivered by the transmitter. [3]

The ideal dummy load provides a standing wave ratio (SWR) of 1:1 at the given impedance. In Telecommunications standing wave ratio ( SWR) is the Ratio of the Amplitude of a partial Standing wave at an antinode (maximum Electrical impedance, or simply impedance, describes a measure of opposition to a sinusoidal Alternating current (AC

See also: Antenna (radio) and Standing wave ratio

Audio

When testing audio amplifiers, it is common to replace the loudspeaker with a dummy load, so that the amplifier's handling of large power levels can be tested without actually producing intense sound. An antenna is a Transducer designed to transmit or Receive electromagnetic waves In other words antennas convert electromagnetic waves into In Telecommunications standing wave ratio ( SWR) is the Ratio of the Amplitude of a partial Standing wave at an antinode (maximum An audio amplifier is an Electronic amplifier that amplifies low-power audio signals (signals composed primarily of frequencies between 20 Hertz to For the Marty Friedman album see Loudspeaker (album A loudspeaker, speaker, or speaker system is an electroacoustical The simplest is a resistor bank to simulate the voice coil's resistance. A voice coil (consisting of a Bobbin, Collar and Winding) is the Coil of Wire attached to the apex of the cone of a Loudspeaker

For loudspeaker simulation, a more complex network is more accurate, however, as actual loudspeakers are reactive and non-linear. This article describes the use of the term nonlinearity in mathematics There are many designs for loudspeaker simulators, which emphasize different characteristics of the actual speaker, such as the voice coil's inductance, mechanical suspension compliance, and cone mass.

See also: Thiele/Small and Electrical characteristics of a dynamic loudspeaker

Power supplies

There are also dummy loads for power supplies, known as load banks. " Thiele/Small " commonly refers to a set of electromechanical Parameters that define the specified low frequency performance of a loudspeaker driver A dynamic Loudspeaker driver's chief electrical characteristic is its Electrical impedance versus Frequency. A load bank is a device which develops an electrical load, applies the load to an electrical power source and converts or dissipates the resultant power output of the source

An electronic load (or e-load) is a device or assembly that simulates loading on an electronic circuit. If an electric circuit has a well-defined output terminal the circuit connected to this terminal (or its Input impedance) is the load. It is used as substitute for a conventional ohmic load resistor.

electronic loads with 800W and 4200W from Höcherl & Hackl
electronic loads with 800W and 4200W from Höcherl & Hackl

As counterpart to a current source, the electronic load is a current sink. A current source is an electrical or electronic device that delivers or absorbs electric current When loading a current source with a fixed resistor one can set one determined load current by the connected load resistor. The characteristic of the electronic load is that the load current can be set and varied in a defined range. The load current is regulated electronically.

The electronic load consumes electric energy and in most cases transforms it into heat energy. Electric energy is the potential energy associated with the conservative Coulomb forces between Charged particles contained within a system, where Thermal energy is the sum of the sensible energy and latent energy. Fans or water-cooled elements are used as coolers. Under certain conditions, energy-recycling into the public power supply system is also possible.

Electronic loads are used in diverse applications, particularly for the test of power supplies, batteries, solar and fuel cells, generators. Power supply is a reference to a source of Electrical power. A device or system that supplies Electrical or other types of Energy to an output load In electronics a battery is a combination of two or more Electrochemical cells which store chemical Energy which can be converted into electrical energy A solar cell or photovoltaic cell is a device that converts Solar energy into Electricity by the photovoltaic effect. A fuel cell is an electrochemical conversion device It produces electricity from Fuel (on the Anode side and an oxidant (on the In Electricity generation, an electrical generator is a device that converts Mechanical energy to Electrical energy, generally using Electromagnetic AC loads are used to test transformers, uninterruptible power supplies (UPS) or onboard power supplies. A transformer is a device that transfers Electrical energy from one circuit to another through inductively coupled Electrical conductors An uninterruptible power supply ( UPS) also known as a continuous power supply ( CPS) or a battery backup is a device which maintains a continuous The equipment and power spectrum of such electronic loads begins with simplest circuits consisting in general of a potentiometer for current setting and a transistor circuit for power transforming. Further develeoped electronic loads supply several operating modes, in most cases constant current, voltage, power and resistance. Nowadays, the equipment offers furthermore the possibility for being controlled analogous or by PLC or remotely by a PC. Settings and measured values such as input voltage and actual load current are indicated on a display.

References

  1. ^ (1990) in Kleinschmidt, Kirk: ARRL Handbook for the Radio Amateur. Newington, Connecticut: American Radio Relay League, 25-21 through 25-23.  
  2. ^ (1990) in Kleinschmidt, Kirk: ARRL Handbook for the Radio Amateur. Newington, Connecticut: American Radio Relay League, 25-21.  
  3. ^ (1990) in Kleinschmidt, Kirk: ARRL Handbook for the Radio Amateur. Newington, Connecticut: American Radio Relay League, 34-22 through 34-28.  

Further reading

See also

External links

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