#Pdc to direct dc adaptor how to

For possible dynamic load resistance, the zener diode should be installed. When the resistance of the load is really fixed, then the zener diode can be omitted, and the voltage will be swinging around the vL between the peak-to-peak of the ripple voltage.

Use voltage rating of equal or higher than 1.5 of vL for the capacitor C1, VC = 1.5*vL.

Select the C1 capacitance value to minimize the peak-to-peak ripple voltage Vrip, C1 = iL/(Vrip* f),.

Select vL as the zener diodeвЂ™s voltage value, with minimum wattage rating Wr = (vL x iL).

Half the R1 to compensate the half-wave rectification, R1 = R1/2.

Make sure the rating for R1 wattage >= power dissipation Pd, Pd = iL*(Vin-vL).

Compute the R1 value, where il = Vin/(R1+RLoad), so R1 = (Vin/iL)-RLoad.

Compute the average load current iL = vL/RLoad.

Below is the step-by-step design procedure: To do this, you can supply the load with a general power supply at its operating voltage (vL), then measure the load current (iL) using an Ampere meter, and deduct the RLoad = vL/iL.

If the resistance of the load is unknown as static resistance, then you can conduct a simple measurement. To design this simple transformer-less AC/DC adapter circuit, you have to know the parameter of the power-line input voltage (Vin) and its frequency (f), the expected (average) voltage output or the voltage at the load (vL), the acceptable voltage ripple at the output (vRipp), and the load resistance (RLoad).

#Pdc to direct dc adaptor how to

The Formula on How to Design The Half-Wave Rectified Transformer-less Adapter Circuit

Isolated driving section of electronic circuitry.

Isolated part of low power micro-controller.

Isolated live charger and supply for low power devices backed with small rechargeable coin battery.

Isolated blinking live indicator for power-line network.

Please be aware that the connected circuit should be isolated from any userвЂ™s touch since the adapter is not isolated from the power-line supply. Half-Wave Rectified Transformer-less Adapter Circuit Application ExamplesД«ecause of limited current specification, we might find that this circuit is only used in very limited application. There are 3 componentвЂ™s values that should be selected when designing with this circuit.

The reason behind this limitation is the use of resistant current limiter (R1) that waste to much power when supplying higher current. Practically, this power supply circuit can be used for devices requiring not more that 10 mA. This circuit is suitable only for devices that draws very small current. The circuit depicted in the schematic diagram shown in the Figure 1.A uses only one high voltage diode, one zener diode, one resistor, and one capacitor. Transformer-less Power Supply Circuit A) Half-Wave Rectified B) Full-Wave Rectified Half-Wave Rectified Transformer-less Power Supply Circuit A schematic diagram of a half-wave rectified transformer-less ac/dc adapter circuit is shown in the Figure 1.A, and the full-wave rectified one is shown in the Figure 1.B.ДЇigure 1. The main application of this types of adapter is where a small power is needed by an isolated device. There two types of this non-isolated power supply adapter circuits: half-wave rectified and full-wave rectified circuits. Warning! This circuit is not isolated from the power-line voltage and causes hazardous electrical shock when get touched!Д«efore discussing this type of circuit, please be aware about this caution: Warning! This circuit is not isolated from the power-line voltage and causes hazardous electrical shock when get touched! Transformer-less Power Supply Adapter Circuit The schematic diagram of the circuits and how to implement them for our design is presented in this article.

There several types of AC/DC adapter circuits, transformer-less (non-isolated), step-down transformer, and switched-mode power supply adapter. Power supply is one of the main element in every electronic circuit, and the right AD/DC adapter circuit should be chosen if we want our device to accept power line voltage as the main supply.