Rongge

12-Bit Digital-to-Analog Converter (DAC) with variable step size . The step size of the converter is variable by selection of the high order data bits. The first DAC, A, has a stable reference current supplied via the 10.24 V reference IC and Rl. R2 provides bias cancellation. As shown, only the first 4 MSB inputs are used, giving a step size of 225/256 2.048/16 = 0.127 mA.  This current supplies the reference for DAC whose step size is then 0.1275/256 = 0.498 µ. Complementary voltage outputs are available for unipolar output and using R3 - R4 = 10, Vout is ± 10.2 V approximately, with a step size (1 LSB) of approximately 5 mV. If desired an op amp can be added to the output to provide a low impedance output with bipolar output symmetrical about ground, if R5 = R6 within 0.05%. Digital 12-Bit dac Circuit Diagram   Note  That offset null is required, and all resistors except R2 and R3 should be 1% high stability types. By using lower order address lines than illustrat...

The electronic devices are very sensitive to the fluctuations in the power fed to them. This problem can be solved by using regulated power supply for them. This power supply circuit is equipped with an adjustable voltage regulator to adjust the output in accordance with the requirement. Adjustable voltage regulators have both line and load regulation which is better than standard fixed regulators. The stepped down AC from the secondary winding of the transformer is fed to the bridge rectifier for rectification. The output has pulsating DC which is filtered by a capacitor C1 (1000uF). This output needs to be stabilized against the input variations by using a voltage regulator IC (LM317) in series with the bridge rectifier. This regulator not only guarantees stable output but can also be adjusted to obtain a desired level of voltage output. The output from the regulator can be varied from 1.2V to 25V. This is achieved by adjusting the value of variable resistor (preset) VR1 (5k). A f...