Canon SPEEDLITE 540EZ Service Manual page 38

Part 2: Technical Information
4.3 Charge Completion Indicator
e Pilot lamp lighting voltage
The following table shows the pilot lamp (LED 1) lighting voltages according to the flash
mode.
Pilot Lamp (LED1) Lighting Voltage [V]
Green| Red _—iz
125 V (0.96 V) 265 V (2 V)
195 V (1.44V) 265 V (2 V)
M1/1, M1/2
MULTI (1 Hz ~ 100 Hz)
(1) The charge (voltage) to C15 (for main flash) is divided at R28 and VR2 via D8, and
is input to pin No.40 of IC7.
(2) When this input voltage is a fixed voltage or more, pins No.45 (green) and No.46
(red) of IC7 each become Low according to this voltage, and the green or red lamp
of the pilot lamp LED1 light to indicate that charging is completed.
e Flow of Operation: (1) > (2)
Figure 2-8 Circuit 3
2-16