Dummy load

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. Contents 1 Radio 2 Audio 3 Power supplies 4 References 5 Further reading 6 See also 7 External links // Radio In radio this device is also known as a dummy antenna or a radio frequency termination. It is a device used in place of an antenna to aid in testing a radio transmitter. 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).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. 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. The simplest is a resistor bank to simulate the voice coil's resistance. For loudspeaker simulation, a more complex network is more accurate, however, as actual loudspeakers are reactive and non-linear. 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. An electronic load (or e-load) is a device or assembly that simulates loading on an electronic circuit. It is used as substitute for a conventional ohmic load resistor. Electronic loads with 800W and 4200W from Höcherl & Hackl As counterpart to a current source, the electronic load is a current sink. 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. 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. AC loads are used to test transformers, uninterruptible power supplies (UPS) or onboard power supplies. 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 developed electronic loads supply several operating modes, in most cases constant current, voltage, power and resistance. Nowadays, the equipment may be controlled by a PLC or remotely by a PC. Settings and measured values such as input voltage and actual load current are indicated on a display. References ^ Kleinschmidt, Kirk, ed (1990). ARRL Handbook for the Radio Amateur. Newington, Connecticut: American Radio Relay League. pp. 25–21 through 25–23.  ^ Kleinschmidt, Kirk, ed (1990). ARRL Handbook for the Radio Amateur. Newington, Connecticut: American Radio Relay League. pp. 25–21.  ^ Kleinschmidt, Kirk, ed (1990). ARRL Handbook for the Radio Amateur. Newington, Connecticut: American Radio Relay League. pp. 34–22 through 34–28.  Further reading Ausias Garrigós and José M Blanes (2005-03-17). "Power MOSFET is core of regulated-dc electronic load". EDN. http://www.edn.com/article/CA509576.html.  Martin Rowe (2005-12-01). "Loads need calibration, too". Ensuring power supply accuracy (Test and Measurement World). http://reed-electronics.com./tmworld/article/CA6291890.html#Loads%20need%20calibration,%20too.  M. B. Borage, S. R. Tiwari, and S. Kotaiah (2003-07-07). "Inductive electronic load for testing of magnet power supplies in particle accelerators". Review of Scientific Instruments 74 (12): 5194–5196. doi:10.1063/1.1622971.  Meng-Yueh Chang, Jiann-Yow Lin, Shih-Liang Jung, Ying-Yu Tzou (1997-06-27). "Design and implementation of a real-time lossless dynamic electronic load simulator". 28th Annual IEEE Power Electronics Specialists Conference 1: 734–739. ISBN 0-7803-3840-5.  B. Singh, S.S. Murthy, S. Gupta (2004-01-14). "Analysis and implementation of an electronic load controller for a self-excited induction generator". Proceedings of Generation, Transmission and Distribution 131 (1): 51–60.  See also Electrical termination Electrical impedance Grid resistor Load bank External links Speaker impedance - ePanorama.net EB5HTC Dummy Load 108W manual - How to make a dummy load 108W v · d · eAnalogue television broadcasting topics Systems 180 lines • 405 lines (System A) • 441 lines • System B (also G and H) • System M Color systems NTSC • PAL • PAL-M • PAL-S • PALplus • SECAM Video Back porch and front porch • Black level • Chrominance • Chrominance subcarrier • Colorburst • Color killer • Color TV • Composite video • Frame (video) • Horizontal scan rate • Horizontal blanking interval • Luminance • Nominal analogue blanking • Overscan • Raster scan • Safe area • Television lines • Vertical blanking interval • White clipper Sound Multichannel television sound • NICAM  • Sound-in-Syncs • Zweikanalton Modulation Frequency modulation • Quadrature amplitude modulation • Vestigial sideband modulation (VSB) Transmission Amplifiers • Antenna (radio)  • Cavity amplifier • Differential gain • Differential phase • Diplexer • Dipole antenna • Dummy load • Frequency mixer • Intercarrier method • Intermediate frequency • Output power of an analog TV transmitter • Pre-emphasis • Residual carrier  • Split sound system • Superheterodyne transmitter • Television receive-only • Television transmitter • Terrestrial television • Transmitter station  • Transposer Frequencies & Bands Frequency offset • Microwave transmission • Television channel frequencies  • UHF • VHF Propagation Beam tilt • Distortion • Earth bulge • Field strength in free space • Knife-edge effect • Noise (electronics) • Null fill • Path loss • Radiation pattern • Skew • Television interference Testing Distortionmeter • Vectorscope  • VIT signals • Zero reference pulse Artifacts Dot crawl • Ghosting • Hanover bars • Sparklies