diff --git a/adafruit_ads1x15/differential.py b/adafruit_ads1x15/differential.py
index 9a4a148..fb0ae56 100644
--- a/adafruit_ads1x15/differential.py
+++ b/adafruit_ads1x15/differential.py
@@ -51,7 +51,8 @@ def read_adc_difference(self, differential, gain=1, data_rate=None):
         - 2 = Channel 1 minus channel 3
         - 3 = Channel 2 minus channel 3
         """
-        assert 0 <= differential <= 3, 'Differential must be a value within 0-3!'
+        if not 0 <= differential <= 3:
+            raise ValueError('Differential must be a value within 0-3!')
         # Perform a single shot read using the provided differential value
         # as the mux value (which will enable differential mode).
         return self._read(differential, gain, data_rate, ADS1X15_CONFIG_MODE_SINGLE)
@@ -64,7 +65,8 @@ def read_volts_difference(self, differential, gain=1, data_rate=None):
         - 2 = Channel 1 minus channel 3
         - 3 = Channel 2 minus channel 3
         """
-        assert 0 <= differential <= 3, 'Differential must be a value within 0-3!'
+        if not 0 <= differential <= 3:
+            raise ValueError('Differential must be a value within 0-3!')
         raw = self.read_adc_difference(differential, gain, data_rate)
         volts = raw * (ADS1X15_PGA_RANGE[gain] / (2**(self.bits-1) - 1))
         return volts
@@ -80,7 +82,8 @@ def start_adc_difference(self, differential, gain=1, data_rate=None):
         function continuously to read the most recent conversion result.  Call
         stop_adc() to stop conversions.
         """
-        assert 0 <= differential <= 3, 'Differential must be a value within 0-3!'
+        if not 0 <= differential <= 3:
+            raise ValueError('Differential must be a value within 0-3!')
         # Perform a single shot read using the provided differential value
         # as the mux value (which will enable differential mode).
         return self._read(differential, gain, data_rate, ADS1X15_CONFIG_MODE_CONTINUOUS)
diff --git a/adafruit_ads1x15/single_ended.py b/adafruit_ads1x15/single_ended.py
index eca1313..1318a46 100644
--- a/adafruit_ads1x15/single_ended.py
+++ b/adafruit_ads1x15/single_ended.py
@@ -47,7 +47,8 @@ def read_adc(self, channel, gain=1, data_rate=None):
         """Read a single ADC channel and return the ADC value as a signed integer
         result.  Channel must be a value within 0-3.
         """
-        assert 0 <= channel <= 3, 'Channel must be a value within 0-3!'
+        if not 0 <= channel <= 3:
+            raise ValueError('Channel must be a value within 0-3!')
         # Perform a single shot read and set the mux value to the channel plus
         # the highest bit (bit 3) set.
         return self._read(channel + 0x04, gain, data_rate, ADS1X15_CONFIG_MODE_SINGLE)
@@ -56,7 +57,8 @@ def read_volts(self, channel, gain=1, data_rate=None):
         """Read a single ADC channel and return the voltage value as a floating point
         result.  Channel must be a value within 0-3.
         """
-        assert 0 <= channel <= 3, 'Channel must be a value within 0-3!'
+        if not 0 <= channel <= 3:
+            raise ValueError('Channel must be a value within 0-3!')
         raw = self.read_adc(channel, gain, data_rate)
         volts = raw * (ADS1X15_PGA_RANGE[gain] / (2**(self.bits-1) - 1))
         return volts
@@ -67,7 +69,8 @@ def start_adc(self, channel, gain=1, data_rate=None):
         function to read the most recent conversion result. Call stop_adc() to
         stop conversions.
         """
-        assert 0 <= channel <= 3, 'Channel must be a value within 0-3!'
+        if not 0 <= channel <= 3:
+            raise ValueError('Channel must be a value within 0-3!')
         # Start continuous reads and set the mux value to the channel plus
         # the highest bit (bit 3) set.
         return self._read(channel + 0x04, gain, data_rate, ADS1X15_CONFIG_MODE_CONTINUOUS)