How are transformerless power supplies calculated?

How are transformerless power supplies calculated?

Maximum Current

1. XC1 = 1/(2 x 3.14 x 50 x 680 x 10-9) = 4683Ω
2. X1 = XC1 // R1 = (XC1 x R1)/ (XC1 + R1) = (4683 x 470 x 103)/ (4683 + 470 x 103) = 4637Ω (Parallel Resistances)
3. Zener Voltage, Vz = 12V.
4. Vin = 230V.
5. Diode Drop, Vd = 0.7V.
6. I = (Vin – Vd – Vz)/(X1 + R1) = (230 – 0.7 – 12)/(4637 + 100) = 0.046A = 46mA.

Is transformerless power supply safe?

Here’s the punchline: transformerless power supplies are safely useable only in situations where the entire device can be enclosed and nobody can accidentally come in contact with any part of it. That means no physical electrical connections in or out — RF and IR are fair game.

How do you make a transformer power supply less?

The conventional method is the use of a step-down transformer to reduce the 230 V AC to a desired level of low voltage AC. The most suitable and low cost method is the use of aVoltage Dropping Capacitor in series with the phase line.

How does a capacitive power supply work?

A capacitive power supply, also called a capacitive dropper, is a type of power supply that uses the capacitive reactance of a capacitor to reduce the mains voltage to a lower voltage. (The capacitance needed increases with the current to be drawn; high capacitance mains-voltage capacitors are expensive and bulky.)

What are X2 capacitors?

Class X2 capacitors are in applications where the peak voltage is equal to below 2500 volts. X3 capacitors are used where the peak voltage is less than or equal to 1200 volts. X class capacitors are rated up to 660Vac and Y capacitors are manufactured with voltage ratings up to 440Vac.

Why transformer is used in power supply?

Transformer: The transformer changes the incoming voltage to the needed outgoing voltage level. These devices may step up or step down the voltage. Typically, the DC voltage required is much less than the incoming AC voltage from the primary power source. The output from this part is unregulated power.

How do you build a power supply calculator?

The formula used to determine the AC voltage required from the transformer is as follows:

1. Vdc= Output voltage.
2. Vreg=Voltage drop of the regulator =3v.
3. Vrec=Voltage drop across diodes=1.25V.
4. Vrip=Ripple voltage=10% of Vdc.
5. Vnom=115V.
6. Vlowline=95V.
7. .9=Rectifier efficiency.

How does a Transformerless power supply circuit work?

Circuit is simple, Voltage dropping capacitor of 0.47uF is connected in series with Phase line of AC, this is a non-polarised capacitors so it can be connected from any side. A 470k ohm resistor is connected in parallel of Capacitor, to discharge the stored current in the capacitor when circuit is switched off, thus preventing from electric shock.

What kind of power supply do you need for a transformer?

Transformerless Power Supply. Generating Low voltage DC, from the 220v or 110v AC mains, is very useful and necessary in the field of electronics. Low voltage DC, like 5v, 6v, 9v, 12v, is used in electronics circuits, LED bulbs, toys and many household electronics items.

What kind of capacitor is used in Transformerless power supply?

And 1000uF/50v capacitor has been used for Filtration, means removing the ripples in resulted wave. And finally a Zener diode of 6.2v/1w is used as voltage regulator. As we know this circuit provides approx. 12v output (see the table above), so this Zener diode regulate it to approx. 6.2v voltage and flow back the extra current.

Can a transformer be used to convert AC to DC?

We have already covered this type of AC to DC conversion, using Transformer in this article Cell Phone Charger Circuit. And yes, we can also convert the High voltage AC into Low voltage DC, without using the Transformer, this is called Transformerless power supply.