5
T1
T2
T
3
V
2
(d)
(c)
(a)
(b)
(e)
(f)
Vs
V
1
Ebb
Ebb
0 V
0 V
0 V
0 V
f=1/T
1
TPT C0012EA
TPT C0012EA
DISCHARGE
SUSTAINING VOLTAGE
INCIDENCE OF UV LIGHT
UVTRON
OUTPUT WAVEFORM
UVTRON
ANODE VOLTAGE
STEP-UP TRANSFORMER
VOLTAGE WAVEFORM
DC-DC CONVERTER
OSCILLATION WAVEFORM
UVtron Operation Waveforms
Figure 4-2: UVTRON Operation Waveforms
SIGNAL PULSES AND BACKGROUND
When the UVTRON is operated with the circuit shown in Figure 4-1, the number of output pulses is increased in
proportion to the incident light intensity at low light levels. However, it will be saturated at the converter oscillation fre-
quency f, as shown in Figures 5 and 6. Because of these characteristics, the UVTRON is better suited for on-off opera-
tion that determines whether or not ultraviolet light is present, rather than for precise measurement of light level.
The next point that must be considered is the background (BG). The BG is caused by sporadic discharges that occur
due to radiation such as cosmic rays and static electricity, even if no ultraviolet light enters the UVTRON. Figure 6 also
shows this phenomenon. When detecting ultraviolet light with the UVTRON, the BG causes false operation if the output
pulses are directly used as the detection signals. Therefore, the signal must be processed to cancel out this background.
Figure 6: UVTRON Output Pulses
Figure 5: UVTRON Sensitivity and Background
0
10
-14
100
(BG)
101
102
103
10
-13
10
-12
10
-11
λ
: 200 nm
1200/min.
TPT B0030EA
TPT B0030EA
INCIDENT LIGHT INTENSITY (W/cm
2
)
LIGHT LEVEL EQUIVALENT TO
LIGHTER FLAME (25 mm) AT 5 m
(SATURATION)
STANDARD TYPE
HIGH SENSITIVITY
TYPE
DC=DC CONVERTER
f=20 Hz
UVtron OUTPUT PULSE (min
-
1
)
UVtron Sensitivity and Background
10 s to 1000 s
0.2 s to 1 s
50 ms
TPT C0013EA
TPT C0013EA
RANDOM
LOW LIGHT LEVEL
Ex.: Lighter flame
(25 mm)
at 5 m away
NO UV LIGHT
(BG)
UVtron Output Pulses
SATURATION
LIGHT LEVEL
DC-DC CONVERTER
f=20 Hz
Содержание UVTRON
Страница 1: ...TECHNICAL INFORMATION How to Use UVTRON...
