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In AC, the usual circuit having a resistor R and a zener in series forms a voltage divider with the diode's dynamic resistance.
Check zener datasheet for Rd, "Dynamic resistance" or "Differential resistance" of the zener (it depends on current).
Example: BZX84C-6V2 at 5mA Rd=6 to 10 ohms
Therefore, output voltage variation will be input ...
3
Yes, you will have some noise left, even if the Zener removes most of it.
Zeners only have the rated voltage over them at rated current. So with a simple resistor-Zener circuit, varying the input voltage will cause the Zener current to vary too, which varies the output voltage.
2
LSCS is one of the best suppliers of these Taiwanese chips.
There is greater stock and wider variety.
The suffix differences are significant but acceptable in your case.
All the G's are Green meaning RoHS meaning lead-free.
I could suggest + or - which differ by only +/- 50 mV. "+" gives slightly more capacity at the expense of charge cycle ...
2
Your transformer should be bolted to the chassis of your project and connect ground from our mains to the chassis. I you are using a plastic project box, it will likely be best to connect to a bolt you are using to mount the transformer to the plastic box. That way, if you ever fry your transformer and you develop a short to the transformer chassis, you'll ...
2
A reverse polarity protection diode is meant to be used in conjunction with a fuse, so that if power is connected backwards the diode will conduct and blow the fuse.
Sometimes this diode will be a zener or TVS (transient voltage suppressor) diode so that it also gives some protection against overvoltage, but very often is is just a plain old rectifier diode ...
2
Typically as drawn D1 would be a zener or avalanche diode and is used for semi-sacrificial overvoltage protection. In this case we are overcoming the reverse bias limit of a diode to perform it's function .
As comment stated you believe the documentation is wrong, in case of series diode it would protect reverse voltage , but the voltage drop and resultant ...
1
The op-amps are connected as a rail splitter to take the floating 10V supply and effectively make it +/-5V.
Loud hum in old audio electronics is typically because of old dried-out electrolytic capacitors in the power supply, such as the 470uF/25V C0002 in your schematic. If you have an ESR meter check that it is within spec, or simply replace older large ...
1
The two are either the same part but renumbered due to expanded features of other variations, or slightly similar.
If you are working from scratch then look at the datasheets for both and decide if they are drop in identical or similar enough you can adapt it.
You have to make sure your using the datasheet for the specific manufacturer version of the dw01 ...
1
Concerns:
3 pin vs 2 pin
the 3rd pin is a dummy plastic pin. The supply is double insulated.
3V to 4.5V
their specs are vague but the 0.05A current and power consumption will reduce with voltage but also increase lifespan somewhat.
I read they are rated for only 200h continuously. (due to vibrator contact arc erosion, I expect)
However if 4.5V* 0.05A ...
1
My guess is that with high voltages if they are being switched synchronously by a pair of FETs, the lumped caps in parallel with the FET Coss helps to balance the voltage changes when switched off with an inductive load.
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