That is good enough, it doesn't need to be very close. From the early description of the DAC I thought this might only output a wave, for example, a smooth wave between 0 and 1.2345 V at a specific frequency.
A DAC takes an integer value (specifically a number between 0 and 2n
-1, where n is the resolution in bits) each cycle and outputs a voltage level between the minimum and the maximum output voltage. For example, on the Due 0 would be 0 VDC
and 4,095 would be 3.3 VDC
; but many DACs have a much wider output voltage range, including negative voltages on some. If you want a constant output, just keep feeding the DAC the same integer value. If you want some sort of waveform vary the integer value so you get the frequency and wave shape you want.
Can you tell me more about this? I am a software guy. I see some very cheap op-amps online, but they all have much larger voltage gains. Also, why 3.85? 3.3V (or 5V) + 3.85V is less than 10V
Amplification is generally expressed as a factor (AV
) that's either the ratio of output over input , AV
, or multiplied with the input to get the desired output, AV
. Regarding the value of 3.85, for some reason I thought the desired voltage was 12 VDC
not 10 VDC
. 3.85 * 3.3 VDC
= 12.705 VDC
So you'd have enough for 12 VDC
plus the forward voltage drop of a standard diode to prevent any back EMF.