# Tag Info

4

In this specific case, the power dissipated by the resistor would double. The more general principal, which is always applicable in all cases is that the average power dissipated by a resistor is the mean value of the instantaneous power calculated over one period. So even if you have an irregular or arbitrary repeating voltage or current waveform, you can ...

4

You can use PWM control under the following two conditions: The average voltage applied does not exceed the rated voltage of the motor. This ensures that the average power rating of the motor is not exceeded. The duration of the PWM pulse does not cause the winding current to saturate. The rotor windings act like an inductor, which smooths the current, but ...

3

Question The OP wishes to control the speed of a DC motor using PWM or regulator. He also wishes to change the direction of the motor. Answer This answer is in two parts: Short and Long. The short answer is kind of an introduction to the long answer. Short Answer Part A - Clarifications A.1 - AC to DC Switching Power Supply and DC-DC Step down voltage ...

3

You're right, should be 64. However, reading the datasheet: There are a maximum of 64 possible programmable addresses using the 6 hardware address pins. It's 6, not 5! Two of these addresses, Software Reset and LED All Call, cannot be used because their default power-up state is ON, leaving a maximum of 62 addresses. Hint: always refer to the official ...

2

Thanks for teaching me an English word new to me. Judder A spasmodic shaking. (like Jitter & Shudder combined) No-load RPM is voltage-controlled (i.e. avg. Vdc = %PWM) and Torque is current-controlled and visa-versa for accleration or braking. The coil commutation converts the DC into AC to provide continuous torque in one direction but depends on ...

2

The MOSFET is acting as a source follower and therefore, the voltage it develops at the source is somewhat less than the voltage applied at the gate. So, if T2 collector can produce (say) 12 volts then T3's gate receives 12 volts and T3's source will be a volt or so lower at 10 or 11 volts (maybe even lower with some FETs). This means that the power ...

2

I need a open loop system where I can Vary the PWM duty cycle within the range using a potentiometer without taking a sample from output. Is it possible with this chip? Clues are in the data sheet such as this lab test fixture: - Look bottom left and you'll see a switch that can be set to position 1 - this applies a 10 kohm feedback resistor to the error ...

1

If you double V and halve D, does the average power dissipation double? Yes it does and it's easily proven by inspection and simple numbers. If R = 1, D = 0.5 and V = 1 volt, the power is 50% of 1²/1 = 0.5 watts. If V doubles to 2 and D halves to 0.25 then the power is 25% of 2²/1 = 1 watt. It applies to any resistor and has nothing to do with thermal time ...

1

If the core saturates, the CS pin will exceed 1V and cause the controller to latch off after 15ms or something like that, until the power is cycled. You can monitor the voltage on that pin and see if that is occurring. Also, measure the primary inductance and see if it is as designed (and double-check your design), preferably under bias if your LCR bridge ...

1

Q1/Q2 is the primary oscillator, PC1 is the photocoupler to feedback Q3 Zener current and thus overvoltage, Q3 is an adjustable Zener. How the Q1/Q2 functions with PWM are unclear, with primary ripple voltage and dynamic load current.

1

I put a resistor between GPIO and gate, then the resistor is going to create a damping effect. Right? Yes. Series resistance is good. Without damping the Gate capacitance and wiring inductance form a high Q tuned circuit that 'rings', causing possibly unacceptable EMI or even circuit misoperation. The higher frequency I have, the less voltage is going to ...

Only top voted, non community-wiki answers of a minimum length are eligible