rc circuit sample free download

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FEATURE ARTICLE Lonne Mays train is ill suited, because the mechanical delay imposed between commanding a new position and that new position being achieved can become greater than what the system requirements will tolerate. TORQUE + SPEED To have both high torque and speed requires you to employ a more potent motor. Such motors don't have to be large, but they do require a heftier V Ч A product delivered to their terminals. Of course, the output of the servo IC can be boosted via a handful of discrete PNP and NPN bipolar junction power transistors, but the biasing of this external array of parts is a nontrivial task. Care must be taken to provide bias tracking stability over temperature, given the PN junction's notorious negative temperature coefficient. Additionally, there is the undesirable inherent inefficiency of the multiple VCE(sat) voltage drops in series with the load, as well as the power wasted in the emitter ballast resistors. Creating an external H-Bridge with discrete MOSFETS is also problematic, because this approach requires different drive circuits for the high-side and low-side FETS and the use of charge pumps. Using a monolithic power H-Bridge ASIC like the MC33887DH is by far an easier means for boosting the output of a servo controller (whether analog or digital). Because this IC incorporates not only the low RDS(on) HBridge but also the gate drive, charge pump, and input logic circuitry, it's a simple yet robust solution for boosting the output of a servo controller IC. The MC33887DH allows you to select motors requiring up to 6 A steady state at up to 30 V. This means motors up to 180 W may be utilized, thus providing both high torque and speed via low-ratio gear trains. Muscle for High-Torque Robotics nalog servomotor control ICs-- such as the venerable MC33030--have facilitated my motion control tasks for many years. Integrated circuits of this genre contain the op-amps to process the information (i.e., voltage) from analog position sensors, the comparators to process position-command voltages (i.e., reference voltages), and the mixed-signal circuitry to close the control loop while taking care of drive functions like window detection, drive direction, braking, and stall detection. The drive capability of these ICs, however, is generally limited to tiny lowvoltage motors (e.g., less than 12 V at less than 500-mA steady-state). a Is your favorite robot getting to be a bit too atrophied for your taste? Does it lack vim and vigor? If so, don't worry. What you need is high torque and speed. With the MC33887D integrated H-Bridge and a little direction from Lonne, you can bulk up your robot in no time. TORQUE VS. SPEED When you're limited to such wimpy motors, the issue of obtaining high torque involves a trade-off between the actuator speed and the required torque or force. This is because a highratio gear train is required to achieve a torque multiplication factor. As a consequence, the speed of the mechanical actuator i