Omega - Numworks

omeganumworks.py

'''conversion functions
''' 

from math import (sqrt, pi, floor, log10)

def powerise10(value):
    """ Returns value as a * 10 ^ b with 0<= a <10
    """
    if value == 0: return 0 , 0
    _neg = value <0
    if _neg : value = -value
    _a = 1.0 * value / 10**(floor(log10(value)))
    _b = int(floor(log10(value)))
    if _neg : _a = -_a
    return _a ,_b
    
def eng(value):
    """Return a string representing value in an engineer friendly notation"""
    _a , _b = powerise10(float(value))
    if -3<_b<3: return "%.4g" % value
    _a = _a * 10**(_b%3)
    _b = _b - _b%3
    return "%.4g*10^%s" %(_a,_b)

BOLTZMAN = 1.38065e-23

def celsius_to_kelvin(temp_celsius):
    '''celsius to kelvin'''
    return 273.15 + temp_celsius

def resistor_vrms(temp_kelvin, resistance, bandwidth):
    '''resistor rms thermal noise'''
    return eng(sqrt((4 * BOLTZMAN)*temp_kelvin*resistance*bandwidth))

def vrms_to_vpp(vrms):
    '''rms to pp'''
    return eng(6.6 * vrms)

def lc_lowpass_cutoff():
    '''3db cutoff of an LC filter'''
    l = float(input('Inductance (H): '))
    c = float(input('Capacitance (F): '))
    a = eng((1/(2*pi*sqrt(l*c))))
    print(eng(a), 'Hz')

def rc_lowpass_cutoff():
    '''3db cutoff of an RC filter'''
    r = float(input('Resistance (Ohms): '))
    c = float(input('Capacitance (F): '))
    a = eng((1/(2*pi*r*c)))
    print(eng(a), 'Hz')

def capacitor_impedance():
    '''Impedance of a Capacitor'''
    freq = float(input('Frequency (Hz): '))
    c = float(input('Capacitance (F): '))
    a = eng((1/(2*pi*freq*c)))
    print(eng(a), 'Ohms')

def inductor_impedance():
    '''Impedance of a Inductor'''
    freq = float(input('Frequency (Hz): '))
    l = float(input('Inductance (H): '))
    a = eng((2*pi*freq*l))
    print(eng(a), 'Ohms')

def dc_voltage_divider():
    '''Voltage Divider'''
    Z1 = float(input('Impedance Top (Ohms): '))
    Z2 = float(input('Impedance Bottom (Ohms): '))
    Vin = float(input('Input Voltage (Volts): '))
    a = eng(Vin*(Z2/(Z1 + Z2)))
    print(eng(a), 'Volts')

def ac_voltage_divider():
    '''ac voltage divider
    '''
    freq = float(input('Operating Freq (Hz): '))
    input_cap = float(input('In-Cap (F, 0 if unused): '))
    input_ind = float(input('In-Ind (H, 0 if unused): '))
    input_res = float(input('In-res (Ohms): '))

    output_cap = float(input('Out-Cap (F, 0 if unused): '))
    output_ind = float(input('Out-Ind (H, 0 if unused): '))
    output_res = float(input('Out-res (Ohms): '))
    
    Vin = float(input('Input Voltage (Vpp): '))

    Z1 = 0
    if input_cap > 0:
        Z1 = (1/(2*pi*freq*input_cap))
    elif input_ind > 0:
        Z1 = (2*pi*freq*input_ind)
    Z1 = Z1 + input_res

    Z2 = 0
    if output_cap > 0:
        Z2 = (1/(2*pi*freq*output_cap))
    elif output_ind > 0:
        Z2 = (2*pi*freq*output_ind)
    Z2 = Z2 + output_res

    a = eng(Vin*(Z2/(Z1 + Z2)))
    print(eng(a), 'Vpp')