My Linux is Ubuntu, and I can't get into root. I looked at /etc/shadow and found the following:Can any experts please tell me how to solve this? Thank you!...
[table] [tr][td][size=3][color=#000][font=宋体]Ultraviolet LED lamp beads, 1W high power and low power SMD LED lamp beads, please recommend manufacturers with good price and quality, as well as driver p...
I am a novice, just contacted with STM, recently there is a project to use STM8 to directly drive the stepper motor (without subdivision driver) for two weeks. Although the motor can run and accelerat...
The hardware used is CH423, 3.3V voltage, pull-up 4.7K, 33pF capacitor filtering
When testing I2C, I found that there was a step in NACK. What caused this?...
With the promotion of the construction of intelligent communities in the country, anti-theft systems have become essential equipment for intelligent communities. Especially in recent years, the urg...[Details]
As cellular phones become more advanced, the power consumption of the system during operation and the power consumption during standby are also increasing. Therefore, the power management design of...[Details]
introduction
For the voltage regulator modules (VRMs) that power the latest computer central processing units (CPUs), power supply designers have historically used multiphase interleaved b...[Details]
Battery life is critical for portable applications. For applications such as smoke detectors, security devices, and thermostats, factory-installed batteries need to last for more than 10 years. The...[Details]
1 Introduction
Building Automation System (BAS) is a distributed monitoring system (DCS) designed according to distributed information and control theory. It is the result of the mutual de...[Details]
1 Introduction
With the development of control, computer, communication, network technology, etc., a new control technology, namely fieldbus, has emerged in the field of industrial control...[Details]
Capacitors
are basic components in various electronic devices and are widely used for bypassing, coupling,
filtering
, tuning, etc. in electronic circuits. However, to use capacitors,...[Details]
We know that the inverter consists of two parts: the main circuit and the control circuit. Due to the nonlinearity of the main circuit (switching action), the inverter itself is a source of harmoni...[Details]
With concerns about the growing energy crisis, motor efficiency has become an important and timely topic. This is because motors use 63% to 70% of the electricity produced in the United States and ...[Details]
0 Introduction
High-precision current source can provide high-precision current supply for precision instruments, and is suitable for automatic measurement tasks of various resistors in semico...[Details]
0 Introduction
Ultrasonic waves
are mechanical waves with a frequency of more than 20KHz, and the propagation speed in the air is about 340 m/s (at 20°C). Ultrasonic waves can be gene...[Details]
This article discusses the six design steps of LED lighting system design in detail: (1) determine the lighting requirements; (2) determine the design goals and estimate the optics; (3) the efficie...[Details]
Direct digital frequency synthesis (DDS) has fast frequency switching and modulation capabilities and is widely used. However, when low power consumption and low cost are the main considerations, D...[Details]
Features
POE technology can ensure the safety of existing structured cabling while ensuring the normal operation of the existing network and minimizing costs. The IEEE 802.3af standard is ...[Details]
With the popularity of digital appliances, rechargeable batteries can be seen everywhere in people's daily lives and have become one of the indispensable daily necessities.
This article gives ...[Details]
Linux and Android
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