Battery Eliminator, Certification : CE Certfied, Feature : Auto Cut, Fast Chargeable

Listing ID #964149

The Battery Eliminator gives variable output voltage of 2.5 to 15V. The use of this Battery Eliminator eliminates the designing of a separate power supply for each project. This is the simplest, cheapest and most reliable circuit, which gives very stable and accurate output as compared to other variable power supply designs. Hence hobbyists can use it very easily.
The circuit gives variable output of 2.5V, 5V, 7.5V, 10V, 12.5V and 15V for input voltage of 16V when P1 is at nearly 25W. The output voltage range can be changed by adjusting preset Battery Eliminator. The minimum voltage range obtained as 2V to 8V. Also the maximum voltage range obtained as 3V to 18V.
About the Circuit :
The circuit uses a standard adjustable voltage regulator IC1, whose output can be selected by rotary switch S1. The adjustable voltages are designed using R1 and combination of resistors R2-R3, R4-R5, R6-R7, R8-R9 and R10-R11. These resistors are selected to give the outputs of 2.5V, 5V, 7.5V, 10V, 12.5V and 15V.  The output voltage rises as the value of resistor between pin1 of IC1 and ground rises. As stated earlier, this output range can be changed by adjusting preset Battery Eliminator. The accuracy of output voltages with the present values of resistors is good enough for most purposes. Although this is the most accurate circuit having stable output.
Calibration :

• For input voltage of 16V and preset is set at 25W, the voltage ranges obtained as 2.5V, 5V, 7.5V, 10V, 13V and 15V with small variations. The first five outputs remain same for input voltage greater than 16V. But it should be noted that the last output increases as the input increases more than 16V.
• When preset is at minimum value, output obtained as 2V, 3V, 4.5V, 5.5V, 6.5V and 8V. Similarly when preset is at maximum value, range obtained as 3V, 6V, 9V, 12V, 15V and 18V.

Power Supply : The circuit requires a DC power supply of 16V. It is designed using 0-12V transformer. Diodes D1, D2, D3, D4 forms a bridge rectifier use to rectify the AC input from transformer. Capacitor C1 is used as a filter capacitor.