26
votes
Is it possible to step down 240 AC to 5 DC without transformer?
Capacitive power supply circuits have been used for decades in things like alarm clocks, small appliances (coffee makers) and the like. They work pretty well for small constant loads without the bulk ...
- 46.9k
16
votes
Accepted
Is this power supply universal input voltage?
The main bulk storage capacitor is rated at 220 volts DC: -
This means that the maximum sinewave RMS voltage that can be applied to the input power connector is 156 volts. This means that it is ...
- 467k
14
votes
Is it possible to step down 240 AC to 5 DC without transformer?
The answer is "yes" - but it is dangerous because there is no isolation and component failure can lead to the full voltage and current from the mains appearing at the output. Here is a ...
- 14.2k
13
votes
Accepted
Drop voltage a bit
Neither is good because the voltage drop is current dependent. If the LEDs are off (such as at power-up) the voltage drop will be minimal. In addition, your target voltage is the absolute max of the ...
- 178k
11
votes
Is this power supply universal input voltage?
No, definitely not.
That 220 volt capacitor is a dead giveaway--and it'll really be dead if you hook this up to 230 volts AC! Rectified 230 volt mains is something like 325 volts, which would ...
- 36.7k
10
votes
Do Step-Down Transformers Increase Total Power Consumption?
You didn't bring up something else -- frequency. You don't mention the country, but I suspect that if they are supplying a mains voltage of \$220\:\textrm{V}_\textrm{AC}\$ then it's probably also \$50\...
- 78.5k
10
votes
Is this power supply universal input voltage?
It's probably a 110V only model.
I think it very unlikely that they built a universal power supply, then printed some of them with fuse values for 125V. If it were a universal power supply, the fuse ...
- 73.1k
9
votes
Best approach to step down 220VAC to 160VAC?
1) Indeed a suitable transformer to make the 160 VAC will be hard to find. And because almost no one needs 160 VAC it will be expensive. If you were not a newbee in EE I could suggest a 120 V to 40 V ...
- 81.2k
9
votes
Accepted
Double Bridge-Rectifier Circuit Question
I tried to analyse path of current during each half-wave, and I don't
see how it could make its way thru the diodes to, obviously bypass the
0.22uF cap, and burn the zener. Anyone care to explain, ...
- 467k
8
votes
Is it possible to convert 19.5V 3.33A to 12V 5.5A?
The answer to your header question is NO!
Input 19.5x3.33 = 64.935 Watts.
Output 12x5.5 = 66 Watts.
So your new output power is higher then your input power which is against the law of conservation ...
- 14.5k
7
votes
The Relation of power heat losses with V & I in transmission lines
simulate this circuit – Schematic created using CircuitLab
Figure 1. A comparison between power transmitted (a) directly and (b) via step-up and step-down transformers on the same pair of wires ...
- 178k
7
votes
Accepted
Do Step-Down Transformers Increase Total Power Consumption?
For an ideal transformer, power in equals power out: it's 100% efficient.
For a realistic AC line step-down transformer, power in is a little bit more than power out: it's not quite 100% efficient, ...
- 8,734
7
votes
Modify The Circuit
If you study closely the application note, where I suppose you found this schematic, it says clearly that this circuit outputs 12V on J2.1 (pin 1 of J2). See also Figure 1 on its first page. So, you ...
- 1,560
7
votes
Accepted
Is it possible to convert 19.5V 3.33A to 12V 5.5A?
Yes, it is possible
power of laptop charger is = 19.5 * 3.33 = 65 Watts
your loads power:
raspberry pi = 5*2.5 = 12.5 watts
Display = 12 * 3 = 36 watts
total power = 48.5 watts
Total power < ...
- 2,076
7
votes
Converting 8V AC to 8V DC - bridge rectifier gets very hot while idling
It should not be getting hot. You are using a switching regulator, which should run cool and draw less current than the output current. The Arduino draws tens of mA and the sound module should draw ...
7
votes
Accepted
Reducing a constant voltage source from 24 V to 12 V
I would swap out the 12V solenoid with a 24V solenoid. All work arounds that are going to be proposed in this thread will probably work in a controlled lab environment, but will give you massive ...
- 175
6
votes
Best approach to step down 220VAC to 160VAC?
I can suggest two approaches:
You may be able to purchase a 1:1 isolation transformer that is rated at the current level that you need and then remove some of the turns from one of the windings.
This ...
- 57.6k
6
votes
Buck converter adjustable output-voltage using digital potentiometer
You don’t need a high voltage device to control the regulator. You only need to alter the current going to its feedback node, which is at 1.23V.
Maxim Integrated makes a family of current source/sink ...
- 56k
5
votes
Accepted
Best design choice: linear regulator or switch converter
Your ripple requirement isn't that hard – what's more problematic is that your output voltage * output current = 300 W!
That's quite a lot. You would not want to burn a couple of volts at 20A over a ...
- 98.4k
5
votes
Accepted
Voltage step down from 12V to 3V3 for cDAQ module
If you just want to measure the coil voltage to sense if the relay is on then a simple voltage divider will do the job.
simulate this circuit – Schematic created using CircuitLab
Figure 1. A ...
- 178k
5
votes
Will a 2000w Step Down Transformer be enough to safely power a Japanese Oven Toaster?
The Japanese standard is 100 V, whereas in the US it is 115-120 V. The higher voltage will cause more heating.
Power into a resistor is proportional to the square of the voltage. Let's say worst ...
- 314k
5
votes
How to convert 5v to 1.5v?
Easy: use an adjustable 3-terminal voltage regulator and connect the "adjust" pin to ground. The downside to this is that for every watt that goes to the motor, you'll burn up around 2.3 watts in the ...
- 46.7k
5
votes
Accepted
Why doesn't the TPS54360DDA work?
You are trying to get 0.8 V out of 24 V input. This is 30:1 ratio, which theoretically requires 1/30 duty cycle for PWM at the fixed switching frequency.
Now, you selected 162 k set resistor, which ...
- 41.9k
5
votes
Step down converter LM2596 with voltage spike on output when powering up, destroys subsequent circuits
The spike problem may be due to a "lag" in feedback (resistor-dividing) circuit. It means there's a delay between feedback voltage and output voltage.
If you have added a capacitor in FB (...
- 847
5
votes
Accepted
54 V input on one, or two 40 V linear regulators? (LM317)
You say a switching regulator is too expensive... but I'm afraid a linear regulator would be even more expensive. You don't specify a current load, but you do say "relatively high amperage". ...
- 36.7k
5
votes
Accepted
Three-phase mains AC/DC conversion to 12 V
Are there other options you see?
Just use a 3-phase flyback power supply like this NXP one: -
There's even a demo board offered so that you can evaluate it.
The above was the first hit on google ...
- 467k
5
votes
Accepted
Why is my circuit powered by a 24 VAC -> 5 VDC stepdown module releasing the magic smoke?
Clearly I'm missing something fundamental, so I seek the wisdom of the
exchange to guide my path. Is there an obvious problem with this
circuit?
The AC to DC converter you linked is not an isolating ...
- 467k
5
votes
Are there any step-down regulators without capacitors for a vacuum environment?
You cannot avoid using capacitors in any kind of real electronics design. Fortunately, people have been figuring out how to make electronics work in vacuum since at least the 1950's, as demonstrated ...
- 46.7k
5
votes
How is this stepping down 12 V?
The IC in the SOT-89 package (upper right, 3 pins plus a tab) appears to be a linear voltage regulator, judging by the large ceramic capacitors C2 and C3 on input and output. Perhaps similar to an ...
5
votes
Accepted
Using resistor to drop voltage in circuit with changing current
A resistor has a voltage across it which is proportional to the current through it. If you double the current through it, you also double the voltage through it. If you half the voltage across it, the ...
- 42.3k
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