Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Does R6 need to be a 1210
Document related concepts
Power factor wikipedia , lookup
Mercury-arc valve wikipedia , lookup
Stepper motor wikipedia , lookup
Electric power system wikipedia , lookup
Audio power wikipedia , lookup
Spark-gap transmitter wikipedia , lookup
Power inverter wikipedia , lookup
Variable-frequency drive wikipedia , lookup
Electrical ballast wikipedia , lookup
Pulse-width modulation wikipedia , lookup
Electrical substation wikipedia , lookup
Immunity-aware programming wikipedia , lookup
Three-phase electric power wikipedia , lookup
Power engineering wikipedia , lookup
Current source wikipedia , lookup
Schmitt trigger wikipedia , lookup
History of electric power transmission wikipedia , lookup
Resistive opto-isolator wikipedia , lookup
Distribution management system wikipedia , lookup
Power electronics wikipedia , lookup
Voltage regulator wikipedia , lookup
Surge protector wikipedia , lookup
Stray voltage wikipedia , lookup
Opto-isolator wikipedia , lookup
Voltage optimisation wikipedia , lookup
Buck converter wikipedia , lookup
Alternating current wikipedia , lookup
Transcript
R9 and R10 R9 = R10 = 32.4k ohm (value selected for quick startup) Maximum AC input voltage = 253V Maximum peak voltage (Vpk) = maximum possible = 253(√2) = 357.8V Maximum voltage across R9 or R10 = 357.8/2) = 178.9V Minimum package size to handle the voltage is 1206 (from Vishay D/CRCW e3 datasheet) Maximum current through R9 and R10 = (357.8/2)/32.4k = 178.9/32.4k = 5.52mA R9 or R10 Power = (V(pk)/2)2/R = (357.8/2)2/32.3k = 178.92/32.4k = 32k/32.4k = 0.987W VCC capacitor = 68uF Time to reach 12V (nominal VCC startup threshold (VCCST)) 12V is a small portion of the 357.8V charging VCC, the current charging the VCC capacitor can be considered as a linear current. IT = CV 5.52mA(T) = 68uF(12V) T = 68u(12)/5.52m = 0.816m/5.52m = 148m seconds to charge the VCC capacitor at startup. = 148m seconds power is dissipated in R9 and R10 Table below from Vishay D/CRCW e3 datasheet. This table is for allowable single pulse wattage versus time. I placed red markers to locate the approximate point of operation. The markers are approximately 148m seconds and approximately 0.987W. The table indicates a 1206 package is not capable of withstanding the power during startup, so the 1210 package is the recommended minimum size for R9 and R10.
