VHC digital currency

1. The HC in 74hc00 is a representative CMOS device. The 74hc00 is a four 2-input NAND gate with a supply voltage range of 2v-6v DC

2. This is a logic chip

3. Rupai 17:48:16

4. Ultra high speed CMOS integrated circuit using "sub micron technology and double layer metal wiring c2mos technology".

5.

Toshiba's chip 4 XOR gate 74vhc86ft

6. The difference of 74hc / LS / HCT / F series chips
1. LS is a low-power Schottky chip, HC is a high-speed COMS chip. LS is slightly faster than HC. HCT is compatible with LS, but its power consumption is low; F is a high speed Schottky circuit
2. LS is TTL level, HC is COMS level
3. LS input open circuit is high level, HC input is not allowed to open circuit, HC generally requires up and down resistance to determine the level when the input is invalid. Ls does not have this requirement
4. LS output pull-down is stronger than pull-up, HC pull-up is the same
5. For different working voltages, LS can only use 5V, while HC can generally use 2V to 6V
6. Different levels. LS is TTL level, its low level and high level are 0.8 and V2.4 respectively, while CMOS is 0.3V and 3.6V respectively when the working voltage is 5V, so CMOS can drive TTL,
but not vice versa
7. The driving ability of LS is generally 5mA for high level and 20mA for low level; The high and low levels of CMOS are 5mA
8. The anti-static ability of CMOS devices is poor, and it is easy to latch, so the input pin of CMOS can not be directly connected to the power supply
74 series IC can be roughly divided into six categories:
. 74 ×× Standard type)< br />.74LS ×× Low power Schottky filter< br />.74S ×× Schottky)< br />.74ALS ×× Advanced low-power Schottky transistor (AVSS)< br />.74AS ×× Advanced schottky< br />.74F ×× High speed)
in recent years, 74 series of high-speed CMOS circuits have appeared, which can be divided into three categories:
. HC is the operating level of COMS
. HCT is TTL working level and can be used interchangeably with 74LS series
. HCU is suitable for CMOS circuits without buffer level
the logic function and pin arrangement of these nine 74 series procts are the same as long as the rear label is the same. Different types of 74 series procts can be selected according to different conditions and requirements. For example, if the supply voltage of the circuit
is 3V, 74hc series procts should be selected. The typical transmission delay of the series level is ns, and the maximum driving current (- IOH / lol) MA

7.

"Mathematics wide angle" is a new unit of compulsory ecation curriculum standard experimental textbook from the first volume of the second grade. It is a new attempt to infiltrate mathematics thinking methods into students

The textbook is based on the life scenes that students are familiar with and interested in. It focuses on infiltrating these mathematical thinking methods into students, putting learning activities in simulated situations, providing students with opportunities for operation and activities, initially cultivating students' awareness of thinking problems in an orderly and comprehensive way, and laying a foundation for students to learn combinatorial mathematics and learning probability statistics in the future

Ding Li edited the book "what to learn and teach in a wide angle of mathematics". This book clearly analyzes the wide angle of mathematics. First of all, it makes a "textbook interpretation" of each topic of "wide angle of mathematics", analyzes the "teaching objectives", "key points and difficulties" of each class hour, and ponders the "editor's intention"

It is not only a basic thinking method in mathematics, but also the basis of algebraic thinking method

If a = B, B = C, then a = C. The real equivalent substitution is: ∀ F (a = B Λ f (a) → f (b)), where f is the generalized equivalent substitution of the formula. For example, "if Li Si is synonymous with Zhang San and Zhang San is human, then Li Si is human"

In order to make it more intuitive, it is illustrated by graphic method. Trees are represented by points, and the lines along which trees are planted are represented by lines. In this way, the problem of tree planting is transformed into the problem of the relationship between the number of "points" on a non closed or closed line and the number of segments of the line between two adjacent points

Digital coding most digital coding uses position representation, that is, any digital quantity can be represented by the sum of some numbers. According to the different positions of these codes in the expression, there are different values. In other words, each position has its own "right"

8. Serial number
dnvhcex5dtd2
IMEI
013054001852757
warranty deadline
May 17, 2013
warranty remaining
313 days
name
iPhone
4S
16GB
White
firmware version
5.1.1
place of purchase
Hong Kong, China
description
iPhone
4S
last activation time
May 18, 2012
ic0141032 5455584931
congratulations, it's a brand new Hong Kong Version, please rest assured to use
if you are satisfied, please adopt
O (∩)_ ∩) O
you can find it online or apple 110

9. 74vhc4040 is a 12 level binary counter, packaged as so-16.

10. One combination, this is their network: http://ke..com/link?url=w0cdbWBwBBdDMyMOVTP2Cwgvu_