SIMPLE TRANSFORMER CIRCUITS SERIES WITH ONE

If the measurement is less than 80 percent of the expected voltage, the fault could lie in either the transformer or the circuitry providing the primary with power. Use the DMM in AC mode to measure the transformer primary. Apply power to the circuitry.

Simple Transformer Circuits Series With One

An example capacitor which is normally used transformerless power supply circuits is shown below:This capacitor is applied in series with one of the mains inputs, preferably the phase line of the AC.When the mains AC enters this capacitor, depending on the value of the capacitor, the reactance of the capacitor comes into action and restricts the mains AC current from exceeding the given level, as specified by the value of the capacitor.However, although the current is restricted the voltage isn't, therefore if you measure the rectified output of a transformerless power supply you will find the voltage to be equal to the peak value of the mains AC, that's around 310V, and this could be alarming for any new hobbyist.But since the current may be sufficiently dropped level by the capacitor, this high peak voltage could be easily tackled and stabilized by using a zener diode at the output of the bridge rectifier.The zener diode wattage must be appropriately selected according to the permissible current level from the capacitor.CAUTION:Please read the caution warning message at the end of the post Advantages of using a Transformerless Power Supply CircuitThe idea is cheap yet very effective for applications that require low power for their operations.Using a transformer in DC power supplies is probably quite common and we have heard a lot regarding it.However one downside of using a transformer is that you cannot make the unit compact.Even if the current requirement for your circuit application is low, you have to include a heavy and bulky transformer making things really cumbersome and messy.The transformerless power supply circuit described here, very efficiently replaces a usual transformer for applications which require current below 100 mA.Here a high voltage metalized capacitor is used at the input for the required stepping down of the mains power and the preceding circuit is nothing but just simple bridge configurations for converting the stepped down AC voltage to DC.The circuit shown in the diagram above is a classic design may be used as a 12 volts DC power supply source for most electronic circuits.However having discussed the advantages of the above design, it will be worth focusing on a few serious drawback this concept may include. Therefore, a simple power transformer will have wires labeled H1, H2, X1.It works by using a high voltage capacitor to drop the mains AC current to the required lower level which may be suitable for the connected electronic circuit or load.The voltage specification of this capacitor is selected such that it's RMS peak voltage rating is much higher than the peak of the AC mains voltage in order to ensure safe functioning of the capacitor. This circuit transformation theory was published by Arthur Edwin Kennelly in 1899.Transformers step up or step down voltage according to the ratios of. The simplest and most commonly used method for ripple reduction is the use of a large.The Y- transform, also written wye-delta and also known by many other names, is a mathematical technique to simplify the analysis of an electrical network.The name derives from the shapes of the circuit diagrams, which look respectively like the letter Y and the Greek capital letter.

The bridge rectifier rectifies this 220V C to a higher 310V DC, due to the RMS to peak conversion of the AC waveform. However, the voltage is not restricted, and therefore the full 220V or whatever may be at the input is allowed to reach the subsequent bridge rectifier stage. Here it may be roughly assumed to be around 50mA. When mains AC mains input is switched ON, capacitor C1 blocks the entry of the mains current and restricts it to a lower level as determined by the reactance value of C1. How the Circuit WorksThe working of this transformless power supply can be understood with the following points: The last but not the least, the above circuit allows voltage surges to enter through it, which may cause serious damage to the powered circuit and to the supply circuitry itself.However in the proposed simple transformerless power supply circuit design this drawback has been reasonably tackled by introducing different types of stabilizing stages after the bridge rectifier.This capacitor grounds instantaneous high voltage surges, thus efficiently safeguarding the associated electronics with it.

The Capacitor C1 becomes the most important part of the circuit since it is the one that reduces the high current from the 220 V or 120 V mains to the desired lower level, to suit the output DC load. C2 finally filters the 12V DC with ripples, into a relatively clean 12V DC.Let's try to understand the function of each of the parts used in the above circuit, in greater details: If a 12V zener is used, this will become 12V and so on.

The resistor R1 is used for providing a discharge path for the high voltage capacitor C1 whenever the circuit is unplugged from the mains input. If you wish to learn the calculations more precisely you can refer to this article. This means, a 2uF will provide 100 mA and so on.

The C2 is the filter capacitor, which smoothens the 100 Hz ripples from the rectified bridge to a cleaner DC. However, the better option could be to use an NTC in place of R2. In order to prevent this we introduce R2. These few initial milliseconds of the switch ON period, allows the full AC 220 V high current to enter the circuit, which may be enough to destroy the vulnerable DC load at the output. It is because, during the instantaneous power switch ON periods, meaning when the input AC is first applied to the circuit, the capacitor C1 simply acts like a short circuit for a few milliseconds. You may feel, when C1 is already there for limiting the current why do we need the R2.

The resistor R2 is mandatory in the circuit, otherwise the zener diode may burn instantly. Improving the DesignThe above transformerless design looks simple, but it has some unavoidable downsides. Please noteВ that I have included a space for an MOV also in the PCB, at the mains input side.

When the voltage drops, the zener stops conducting switching OFF the transistor, and the cycle keeps repeating at a fast rate, enabling a stabilized DC output voltage that is almost equal to the zener voltage value. In this situation, the transistor conducts and shorts circuits the DC causing the voltage to drop. The power transistor ST13003 is used like a shunting device, which grounds the entire power from the capacitor C1 as soon as the output DC from the bridge tries to reach above the zener diode level.

So over all 195 - 204 LED bulbs in final rope. So over all 390 - 408 LED bulbs in final rope.So please suggest me best possible driver circuit to operateWe have another rope of 3 strings.The string is made up of about 65 to 68 LED of 3 Volt in series approximately at a distance of let us say 2 feet , such 3 strings are roped together to make one string so the bulb placement comes out to be at 4 inches in final rope.