Although it may seem that there is no problem since a low current is used to control the ONOFF of a large current, the consumption of power in the control circuit raises the temperature, so that there is a limit to how small the circuit can be made.This was made possible by advances in semiconductor technology that took place in Japan the United States, and European countries.
The electronic technology to drive and control motors has come to be referred to as power electronics. In the use of semiconductor devices for motor control, however, advances occurred side by side in analog and digital devices. The servo motor is used for the same purpose but is analog-controlled; it was developed by modifying the DC motor for this application. What do we mean by analog This is explained in Fig. We shall consider the control of a DC motor. There are two terminals, A and B, and we assume that an electronic circuit is used to control the voltage on terminal B. Since the supply voltage is V, the motor is subjected to a voltage which is obtained by subtracting the voltage at terminal B motor from V. Download tantri basa kelas 5In analog control, the voltage applied to the motor is controlled in a continuous, smooth manner, which has the advantage of achieving a smooth rotation, but the transistors or other semiconductor devices are subjected to the difference between the supply and motor voltages. The product of this voltage difference and the current flowing is the power consumed in the electronic device. For example, if there is a 5V voltage difference and 4A current flow, a loss of 20W occurs. In the former, the electronic circuit operates so that the voltage on terminal B varies between 0 and V (e.g., 12V, 24V) in a smooth manner. When the electronic circuit is a switching circuit, the voltage on terminal B is either 0 or V, which we may consider as a digital-control method. Here, control is done to achieve either of two states, application of the supply voltage, V, or 0, and their respective times. The stepping motor is controlled by a relatively simple digital method. A method widely used today is Pulse-width modulation, which is used to control brushed and brushless DC motors. In early times, the semiconductor device used for analog control was the bipolar junction transistor. Today, analog control is done by a device called the power operational amplifier, or op-amp. The op-amp is a convenient device that functions as an analog computer. The insulated-gate bipolar transistor (IGBT), which combines the features of the junction transistor and MOSFET, is an important device that supports power electronics. Mariner magnum 40 hp manual 1996However, the junction transistor had a shortcoming as a switching device. This was the need to pass current between the base and emitter to switch it on, which makes for a less-than-ideal switch.
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