使用 Python 进行高级 LED 串联电阻值和功耗计算

# Configuration parameters
from UliEngineering.Electronics.LED import *
from UliEngineering.Electronics.Resistors import *
from UliEngineering.EngineerIO import *

### BEGIN OF CONFIGURATION ###
desired_led_current = "8mA"
vsupply = "3.3V"
vforward_min = "1.8V"
vforward_max = "2.4V"
# Typical forward voltage is often the average of min and max
# (or you can enter a specific typical value if you have one)
vforward_min_val = normalize_numeric(vforward_min)
vforward_max_val = normalize_numeric(vforward_max)
vforward_typ_val = (vforward_min_val + vforward_max_val) / 2
vforward_typ = f"{vforward_typ_val}V"
tolerance = "1%" # typical 1% or 5%
# Choose whether to select the next higher or lower standard resistor value
# ("higher" yields less current, "lower" yields more current)
higher_or_lower_resistor = next_higher_resistor
### END OF CONFIGURATION ###

print(f"LED Series Resistor calculation for a LED with Vf min..typ..max: {vforward_min}..{vforward_typ}..{vforward_max}")
print()

# Helper: list of forward voltages (min, typ, max)
vforward_vals = [vforward_min_val, vforward_typ_val, vforward_max_val]

# Compute ideal series resistors for min, typ and max forward voltages
series_resistors = [led_series_resistor(vsupply, desired_led_current, vf) for vf in vforward_vals]
# Pre-format resistor values for concise printing
series_resistors_fmt = [format_value(r, 'Ω') for r in series_resistors]
print(f"Ideal LED series resistor for {vsupply} and {desired_led_current}: {series_resistors_fmt[0]}..{series_resistors_fmt[1]}..{series_resistors_fmt[2]}")

# Power dissipated by the ideal resistor for each forward voltage
powers_ideal = [led_series_resistor_power(vsupply, desired_led_current, vf) for vf in vforward_vals]
# Pre-format power values for concise printing
powers_ideal_fmt = [format_value(p, 'W') for p in powers_ideal]
print(f"Power dissipated by the ideal series resistor: {powers_ideal_fmt[0]}..{powers_ideal_fmt[1]}..{powers_ideal_fmt[2]}")

# Get the next higher standard E24 resistor value
print()
# Choose standard resistor based on the TYPICAL (middle) ideal value
standard_series_resistor = higher_or_lower_resistor(series_resistors[1], sequence=e24)
standard_series_resistor_fmt = format_value(standard_series_resistor, 'Ω')
print(f"Next standard resistor value: {standard_series_resistor_fmt}")

# Calculate the actual current through the LED & series resistor for min..typ..max when selecting the next standard resistor
standard_currents = [led_series_resistor_current(vsupply, standard_series_resistor, vf) for vf in vforward_vals]
# Pre-format currents for concise printing
standard_currents_fmt = [format_value(I, 'A') for I in standard_currents]
print(f"Current through the LED & series resistor: {standard_currents_fmt[0]}..{standard_currents_fmt[1]}..{standard_currents_fmt[2]}")

# Calculate the actual power dissipation in the selected standard resistor for each forward voltage
standard_powers = [power_dissipated_in_resistor_by_current(standard_series_resistor, I) for I in standard_currents]
# Pre-format powers for concise printing
standard_powers_fmt = [format_value(p, 'W') for p in standard_powers]
print(f"Power dissipated by the {standard_series_resistor_fmt} series resistor: {standard_powers_fmt[0]}..{standard_powers_fmt[1]}..{standard_powers_fmt[2]}")

# Calculate how much maximum current would be permissible for the series resistor
max_current = led_series_resistor_maximum_current(resistance=standard_series_resistor, power_rating="250mW")
print(f"Maximum permissible current for the {standard_series_resistor_fmt} series resistor: {format_value(max_current, 'A')}")

# Compute the power dissipation if the resistor is at the lower or upper end of its tolerance
print()
# Get the tolerance bounds
tolerance_bounds = resistor_tolerance(resistance=standard_series_resistor, tolerance=tolerance)
lowest_resistor_value = tolerance_bounds.lower
highest_resistor_value = tolerance_bounds.upper
lowest_resistor_value_fmt = format_value(lowest_resistor_value, 'Ω')
highest_resistor_value_fmt = format_value(highest_resistor_value, 'Ω')

# Lower-end (smaller resistance -> higher current)
print(f"If the {standard_series_resistor_fmt} resistor is at the lower end of its {tolerance} tolerance ({lowest_resistor_value_fmt}):")
lowest_resistor_currents = [led_series_resistor_current(vsupply, lowest_resistor_value, vf) for vf in vforward_vals]
lowest_resistor_currents_fmt = [format_value(I, 'A') for I in lowest_resistor_currents]
print(f"Current through the LED & {lowest_resistor_value_fmt} series resistor: {lowest_resistor_currents_fmt[0]}..{lowest_resistor_currents_fmt[1]}..{lowest_resistor_currents_fmt[2]}")
lowest_resistor_powers = [power_dissipated_in_resistor_by_current(lowest_resistor_value, I) for I in lowest_resistor_currents]
lowest_resistor_powers_fmt = [format_value(p, 'W') for p in lowest_resistor_powers]
print(f"Power dissipated by the {lowest_resistor_value_fmt} series resistor: {lowest_resistor_powers_fmt[0]}..{lowest_resistor_powers_fmt[1]}..{lowest_resistor_powers_fmt[2]}")

# Upper-end (larger resistance -> lower current)
print()
print(f"If the {standard_series_resistor_fmt} resistor is at the upper end of its {tolerance} tolerance ({highest_resistor_value_fmt}):")
highest_resistor_currents = [led_series_resistor_current(vsupply, highest_resistor_value, vf) for vf in vforward_vals]
highest_resistor_currents_fmt = [format_value(I, 'A') for I in highest_resistor_currents]
print(f"Current through the LED & {highest_resistor_value_fmt} series resistor: {highest_resistor_currents_fmt[0]}..{highest_resistor_currents_fmt[1]}..{highest_resistor_currents_fmt[2]}")
highest_resistor_powers = [power_dissipated_in_resistor_by_current(highest_resistor_value, I) for I in highest_resistor_currents]
highest_resistor_powers_fmt = [format_value(p, 'W') for p in highest_resistor_powers]
print(f"Power dissipated by the {highest_resistor_value_fmt} series resistor: {highest_resistor_powers_fmt[0]}..{highest_resistor_powers_fmt[1]}..{highest_resistor_powers_fmt[2]}")

LED Series Resistor calculation for a LED with Vf min..typ..max: 1.8V..2.1V..2.4V

Ideal LED series resistor for 3.3V and 8mA: 187 Ω..150 Ω..112 Ω
Power dissipated by the ideal series resistor: 12.0 mW..9.60 mW..7.20 mW

Next standard resistor value: 150 Ω
Current through the LED & series resistor: 10.00 mA..8.00 mA..6.00 mA
Power dissipated by the 150 Ω series resistor: 15.0 mW..9.60 mW..5.40 mW
Maximum permissible current for the 150 Ω series resistor: 40.8 mA

If the 150 Ω resistor is at the lower end of its 1% tolerance (148 Ω):
Current through the LED & 148 Ω series resistor: 10.1 mA..8.08 mA..6.06 mA
Power dissipated by the 148 Ω series resistor: 15.2 mW..9.70 mW..5.45 mW

If the 150 Ω resistor is at the upper end of its 1% tolerance (152 Ω):
Current through the LED & 152 Ω series resistor: 9.90 mA..7.92 mA..5.94 mA
Power dissipated by the 152 Ω series resistor: 14.9 mW..9.50 mW..5.35 mW