Found a very good tutorial written by XP Power that concisely (short yet complete) covered all topics about power circuits that every circuit hobbyist should be aware of.
Here’s the book:
Every concept about electrical power
Reply
Descriptive names for logic operations on a pair (x, y)
It reads as “The output is TRUE only when the reduction 
meets the description of the operations below”
0 inputs:
- Constant: gives the same hard-coded result regardless of inputs
1 input:
- Transfer: Hardwired to one of the inputs
- Complement: NOT
2 inputs (symmetric):
- Comparison: different (XOR), identical (NXOR or equivalence)
- Arithmetic: AND, OR and its complements NAND, NOR
2 inputs (asymmetric):
- Inhibition: ONLY 1 followed by 0 is an inhibition. It’s a WHITE-list: anything else is not an inhibition (starting with 0 doesn’t inhibit)
- Implication: ANYTHING GOES as long as 1 is be followed by 1. It’s a BLACK-list: anything else qualifies as an implication (starting with 0 does not break the implication)
Implication is the complement of Inhibition, as the only case that breaks an implication is inhibition.
This ‘operator’ instead of truth-table view is more often used in electrical engineering than in computer science. There are many names for the same thing, but I put in some thought to find the intuitive words to make it easy to understand and remember
WARNING: Those there are tempting faint similarities between logic and set theory, there’s no direct tight duality between the two. Whitelist/Blacklist in inhibition/implication do not make sense with set-diff/subset as we are talking about a one-shot relationship here in logic, while set theory talks about the relationship between elements picked after it is quantified by “for all” vs “there is”. i.e. Truth table do not mix with sets
日台大辭典
Oh! Humanity
Onion used to my favorite satire newspaper before it was taken over by the wokes. When I was in college, some teaching assistants read us an article as a treat before starting a session. Here’s one of my favorite headlines. Here’s one of my favorite
Newborn Loses Faith In Humanity After Record 6 Days
https://www.theonion.com/newborn-loses-faith-in-humanity-after-record-6-days-1819573929
It took me 7 years. I guess I was slow.
I grew up in Hong Kong and I can tell you for sure that you are going to have a very hard time surviving there if you are not a hardcore cynic. People are very harsh to each other but most are sticklers to the rules and contracts to the letter (they believe in the rule-OF-law), to the extent that some might find them inflexible or outright cruel (this is especially true with bus drivers in Hong Kong nowadays) .
In other words, people there feel comfortable taking advantage of others, but 99.9% of time they do it within legal boundaries (like exploiting scenarios not considered when the contracts are drafted) as they are not bold legal risk takers. It’s not a forgiving city because Hongkong is geographically too close to the land of crooks so every sign of kindness we show are seen as signs of weakness ready to be exploited. Kindness just doesn’t pay in Hong Kong.
Socialist (Chinese Communist Party) is a shit-magnet, identifying the nastiest people in any population. Hong Kong Protests in 2019 showed me people aren’t predominantly bad. I might have picked up a little bit of faith in humanity again after seeing the spirits of the freedom-fighters. The scumbags I should have hated with passions are now wagging their tails and licking the boots of the Chinese Communist Party.
E5070B / E5071B shutting itself down immediately after turning on
Got a second customer coming in today with a E507XB series network analyzer that does not turn on. Looks like it’s a common problem within the model series.
If the unit turns on without the CMOS battery but it doesn’t turn on the 2nd time after the CMOS was cleared, you have a very expensive problem which likely I’m the only person who can solve it because it’s months of effort tracing the circuit and the timings inside. I regretted chasing down the rabbit hole and spent more labor than 3 good unit’s costs for the few grands I’ve charged, but I might be able to recoup the labor in the future as more of the E507XB fails the same way.
UNLESS it’s a SC815E (there are 2 revisions that uses different motherboard), it’s NOT the motherboard or the power supply. I’ve seen some faulty SC815E doing the same on other model series, but not the VP22s (I replaced 4~5 different VP22s, they all do the same thing). It’s some good timing issues that’s hard to pinpoint to a specific module (you can replace everything on the digital side and it still doesn’t work) which I had to design, build and test a special circuit to correct it.
If you have a unit E5060 series or E5070 series VNA (Vector Network Analyzer) that doesn’t boot, I’m likely to have the exact experience fixing it. Of course I’m open to solving other problems with the analyzer as well. I offer free eval (no fix, no fee). Please email me at owner@humgar.com or call me at 949-682-8145.