Recent content by Michael Neo

@DaveE The table is from the notes. Ah! In binary, the sequence in the table is 1, 2, 4. 3 has been ommitted. Since they increase by a fixed amount, 011 (i.e. 3) gives 3/12 of V output.

Thank you both for taking the time to reply. The three bit DAC is exactly the same as the one in the problem statement. Here are the notes:

I thought this method might work, but when you sub the numbers into the formula it doesn't match the outputs in the table above. https://uk.tek.com/blog/tutorial-digital-analog-conversion-%E2%80%93-r-2r-dac

A small piece of advice to get me started would be much appreciated!

There is an example of a two bit DAC in the notes but not a three bit DAC. Three digital inputs results in 8 analogue outputs: 23 = 8 Digital Inputs_________Analogue Outputs CBA 000____________________0 001____________________1/12 x 24 = 2 V 010____________________2/12 x 24 = 4 V...

Thank you for the excellent advice and support, NascentOxygen.

R1 = 150 Ω R2 = 850 Ω This question was easier than the example question. It is important to read and understand the diagram before throwing things onto the page in panic.

Here's the diagram with calculations:

In the example, the purpose of R2 is to reduce the current to the Opto-triac LEDs minimum operating current (i.e. 2 mA). The operating current is 10 mA but only 2 mA is needed through the opto-isolator LED. Therefore, 10 mA − 2 mA = 8 mA will need to be removed by the use of R2: R2 =...

This is a very straightforward question: (a) if you relax and read the diagram first and understand what is happening (especially the impact of the diodes on the direction of the current); (b) because of the direction of current flow, the function of R2 is not the same as the example given in...

Yes. Then:

The direction of the current is given in the diagram. Current passing through a diode can only go in one direction, called the forward direction. The diode allows current to flow in the direction of the arrow. So, the current does split at the first node.

If so, then R2 doesn't perform the function outlined above. The voltage across R2 = 3.3 - 1.6 = 1.7 V So, R1 is simply: R1 = 1.7/0.002 R1 = 850 Ω

I assumed that the current flows in an anti-clockwise direction. However, the components indicates the current splits at the first node.

I am baffled how to calculate the current in that part of the circuit. I have total voltage but not total current or total resistance.