import time

import Adafruit_MCP4725

import numpy as np

dac = Adafruit_MCP4725.MCP4725()

freq = 500
maxbit = 4096
startzeit = time.time()

while True:

 zeitpunkt = time.time()
 deltat = startzeit - zeitpunkt

 signal = ((np.sin(2 * np.pi * freq * deltat) +1) /2) * maxbit
 signalround = int(round(signal))

 dac.set_voltage(signalround)