The output is a negative going staircase waveform with 15 steps of -).5V each. The graph with the analog outputs versus possible combinations of inputs is shown below.ĭigital-to-Analog Converter Circuit – Binary-Weighted Resistors Method Graph V0 = -Rf *() – where each of the inputs b3, b2, b1, and b0 may either be HIGH (+5V) or LOW (0V). Naturally, the output will be maximum if the switches (b0-b3) are closed This overall current is then converted to its proportional output voltage. The current through Rf will be the sum of these currents. Thus, according to the position (ON/OFF) of the switches (bo-b3), the corresponding “binary-weighted” currents will be obtained in the input resistor. R/2 will be connected to the positive supply of the +5V.Ĭurrent through R will become twice the value of current (1mA) to flow through Rf. It will be connected directly to the +5V.Ĭurrent through feedback resistor, Rf = 0.5mA (Since, Input bias current, I B is negligible) The circuit is basically working as a current to voltage converter. Thus, a corresponding 16 outputs of analog will also be present for the binary inputs.įour switches from b0 to b3 are available to simulate the binary inputs: in practice, a 4-bit binary counter such as a 7493 can also be used. We know that, a 4-bit converter will have 2 4 = 16 combinations of output.
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