quick detection of flame from distance, compact uv sensor with high sensitivity and wide directivity, suitable for flame detectors and fire alarms. flame detectors for gas / oil lighters and matches fire alarms combustion monitors for burners inspection of ultraviolet leakage detection of discharge ultraviolet switching flame sensor uvtron r2868 information furnished by hamamatsu is believed to be reliable. however, no responsibility is assumed for possible inaccuracies or omissions. specifications are subject to change without notice. no patent rights are granted to any of the circuits described herein. ?008 hamamatsu photoni cs k.k. subject to local technical requirements and regulations, availability of products included in this promotional material may var y. please consult with our sales office. specifications applications hamamatsu r2868 is a uvtron ultraviolet on/off detector that makes use of the photoelectric effect of metal and the gas multiplication effect. it has a narrow spectral sensitivity of 185 nm to 260 nm, being completely insensitive to visible light. unlike semiconductor detectors, it dose not require optical visible-cut fil- ters, thus making it easy to use. in spite of its small size, the r2868 has wide angular sensitivity (directivity) and can reliably and quickly detect weak ultraviolet radiations emitted from flame due to use of the metal plate cath- ode (eg. it can detect the flame of a cigarette lighter at a distance of more than 5 m.). the r2868 is well suited for use in flame detectors and fire alarms, and also in detection of invisible discharge phenomena such as corona discharge of high-voltage transmission lines. general maximum ratings characteristics (at 25 c) unit parameter spectral response window material weight 185 to 260 uv glass approx. 1.5 nm g description / value unit parameter supply voltage peak current 1 average discharge current 2 operating temperature 400 30 1 -20 to +60 v ma ma c value unit parameter discharge starting voltage (with uv radiation) (dc) recommended operating voltage (dc) background 3 sensitivity 4 max. max. typ. 280 325 25 10 5000 v v min -1 min -1 value 1 this is the maximum momentary current that can be handled if its full width at half maximum is less than 10 s. 2 if the tube is operated near this or higher, the service life is notice- ably reduced. use the tube within the recommended current values. 3 measured under room illuminations (approx. 500 lux) and recommen- ded operating conditions. note that these values may increase if the following environmental factors are present. (1)mercury lamps, sterization lamps, or halogen lamps are located nearby. (2)direct or reflected sunlight is incident on the tube. (3)electrical sparks such as welding sparks are present. (4)radiation sources are present. (5) high electric field (including static field) generates across the tube. 4 these are representative values for a wavelength of 200 nm and a light input of 10 pw/cm 2 . in actual use, the sensitivity will vary with the wavelength of the ultraviolet radiation and the drive circuitry employed. note: figure: uvtron's spectral response and various light sources tpt b0009eb 200 300 400 500 600 700 800 900 100 wavelength (nm) relative sensitivity, relative intensity (arbitrary unit) 100 50 0 ultraviolet visible infrared gas flame tungsten light sunlight uvtron's spectral response
tpt 1008e02 dec. 2008 ip figure 2: angular sensitivity (directivity) figure 3: dimensional outline (unit: mm) figure 4: recommended operating circuit flame sensor uvtron r2868 hamamatsu photonics k.k., electron tube division 314-5, shimokanzo, iwata city, shizuoka pref., 438-0193, japan, telephone: (81)539/62-5248, fax: (81)539/62-2205 u.s.a.: hamamatsu corporation: 360 foothill road, p. o. box 6910, bridgewater. n.j. 08807-0910, u.s.a., telephone: (1)908-231-0960, fa x: (1)908-231-1218 e-mail: usa@hamamatsu.com germany: hamamatsu photonics deutschland gmbh: arzbergerstr. 10, d-82211 herrsching am ammersee, germany, telephone: (49)8152-375-0, f ax: (49)8152-2658 e-mail: info@hamamatsu.de france: hamamatsu photonics france s.a.r.l.: 19, rue du saule trapu, parc du moulin de massy, 91882 massy cedex, france, telephone: (3 3)1 69 53 71 00, fax: (33)1 69 53 71 10 e-mail: infos@hamamatsu.fr united kingdom: hamamatsu photonics uk limited: 2 howard court, 10 tewin road welwyn garden city hertfordshire al7 1bw, united kingdom, teleph one: 44-(0)1707-294888, fax: 44(0)1707-325777 e-mail: info@hamamatsu.co.uk north europe: hamamatsu photonics norden ab: smidesv ? gen 12, se-171-41 solna, sweden, telephone: (46)8-509-031-00, fax: (46)8-509-031-01 e-mail: info@hamamatsu.se italy: hamamatsu photonics italia: s.r.l.: strada della moia, 1/e, 20020 arese, (milano), italy, telephone: (39)02-935 81 733, fax: (39)02-935 81 741 e-mail: info@hamamatsu.it web site www.hamamatsu.com uvtron driving circuit c3704 series (sold separately) tpt b0010ea tpt c0003eb precautions for use ultraviolet radiation the uvtron itself emits ultraviolet radiation in operation. when using two or more uvtrons at the same time in close position, care should be taken so that they do not optically interfere with each other. vibration and shock uvtrons have passed vibration and shock tests in compliance with iec 60068-2-6 (sinusoidal vibration test 1.5 mm peak to peak, 100 m/s 2 , 10 hz to 500 hz) and iec 60068-2-27 (shock test 1000 m/s 2 , 11 ms). however if subjected to strong mechanical shocks such as drop impacts, the glass envelope may crack or internal electrodes may deform resulting in poor electrical characteristics. so use extreme caution when handling the uvtron. if the leads are machined or cut with a wire cutter, the internal electrodes may be subjected to vibrations or shocks greater than the above tests, resulting in poor electrical characteristics as in the case where they are subjected to drop impacts. polarity connect the uvtron with correct polarity. should it be connected with reverse polarity, operating errors may occur. warranty the uvtron is covered by a warranty for a period of one year after delivery. the warranty is limited to replacement of any defective tube due to defects traceable to the manufacturer. anode cathode anode cathode 90 60 60 30 30 0 90 100 % 80 60 40 20 100 % 80 60 40 20 vertical viewing (left fig.) horizontal viewing (left fig.) uv emission point 90 60 60 30 0 90 cathode 5 12 uv glass bulb anode a a' 9.0 0.5 8 1 23 1 8 1 18 max. 32 min. 44 max. 4 1 cathode lead anode cathode anode lead 12 max. side view top view a a' lead: 0.65 0.05 cathode anode 1000 pf + dc 325 v 25 v 220 pf 500 v 10 m ? 4.7 k ? * anode uvtron r2868 cathode pulse output 10 k ? * be sure to connect the 4.7 k ? resistor within 2.5 cm from the anode lead end of uvtron. i tpt a0023eb hamamatsu also provide the driv- ing circuit c3704 series for r2868 operation. c3704 series include a high volt- age power supply and a signal processing circuit in printed circuit board, which allows to operate r2868 easily as a flame sensor with the low input voltage (dc 5 v to 30 v) only. for the details, please refer to the data sheet of c3704 series.
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