In this question, we are missing some of the information that is necessary in order to answer this question properly. However, we can look at what a relational database is in order to help you answer the question on your own.
A relational database is a set of tables from which data can be accessed. This can take place even without the need to reorganize the database tables. The programming interface of a relational database is the Structured Query Language (SQL). This approach was invented by E. F. Codd, who came up with it in 1970 while he was a programmer at IBM.
The following statement best describes how a hearing aid works, An implant bypasses parts of the cochlea and sends messages to the brain, where they are then recognized as sound.
Explanation:
- The hearing aid works as An implant bypasses parts of the cochlea and sends messages to the brain, where they are then recognized as sound.
- A hearing aid is a device designed to improve hearing by making sound audible to a person with hearing loss.
- Modern devices uses all sophisticated digital signal processing to try and improve the speech understanding, intelligibility and comfort for the user, such as signal processing
- Almost all hearing aids in use in the US are digital hearing aids Devices similar to hearing aids include cochlear implant.
- Early devices, such as ear trumpets or ear horns, were the passive amplification cones which were designed to gather the sound energy and directly goes into the ear canal.
- Most common issues with hearing aid fitting and use are the occlusion effect, loudness recruitment, and understanding speech in noise.
Answer:
a) Ql=33120000 kJ
b) COP = 5.6
c) COPreversible= 29.3
Explanation:
a) of the attached figure we have:
HP is heat pump, W is the work supplied, Th is the higher temperature, Tl is the low temperature, Ql is heat supplied and Qh is the heat rejected. The worj is:
W=Qh-Ql
Ql=Qh-W
where W=2000 kWh
Qh=120000 kJ/h
b) The coefficient of performance is:
c) The coefficient of performance of a reversible heat pump is:
Th=20+273=293 K
Tl=10+273=283K
Replacing:
Answer:
You need a 120V to 24V commercial transformer (transformer 1:5), a 100 ohms resistance, a 1.5 K ohms resistance and a diode with a minimum forward current of 20 mA (could be 1N4148)
Step by step design:
- Because you have a 120V AC voltage supply you need an efficient way to reduce that voltage as much as possible before passing to the rectifier, for that I recommend a standard 120V to 24V transformer. 120 Vrms = 85 V and 24 Vrms = 17V = Vin
- Because 17V is not 15V you still need a voltage divider to step down that voltage, for that we use R1 = 100Ω and R2 = 1.3KΩ. You need to remember that more than 1 V is going to be in the diode, so for our calculation we need to consider it. Vf = (V*R2)/(R1+R2), V = Vin - 1 = 17-1 = 16V and Vf = 15, Choosing a fix resistance R1 = 100Ω and solving the equation we find R2 = 1.5KΩ
- Finally to select the diode you need to calculate two times the maximum current and that would be the forward current (If) of your diode. Imax = Vf/R2 = 10mA and If = 2*Imax = 20mA
Our circuit meet the average voltage (Va) specification:
Va = (15)/(pi) = 4.77V considering the diode voltage or 3.77V without considering it