The construction of a unique power supply circuit that can give the output range of power voltages from 0 to 15V is explained in this article.
Also it can power a lot of electrical devices because it has the 5 amp current capacity.
Further because this power supply remains stable the voltage will not change even if the input power differs somewhat.
Circuit Working:
Parts List:
| Component | Quantity |
|---|---|
| Resistors (All resistors are 1/4 watt unless specified) | |
| 1k | 4 |
| 10k | 2 |
| R6 (Maximum output current < 5A value not specified) | 1 |
| Potentiometer 10k | 1 |
| Preset 22k | 1 |
| Capacitors | |
| Electrolytic 4700μF 35V, 100μF 25V | 2 each |
| Semiconductors | |
| IC 741 | 1 |
| Transistors 2N2222, 2N3055, BC547 | 1 each |
| Zener Diodes 10V , 5.6V | 1 each |
| Bridge Rectifier 6A4 | 4 |
| Transformer 18V 5A | 1 |
Using P1 potentiometer is controlled by power supply which is adjusted between a few volts and 15V while P2 preset controls the maximum limit between 15V and 0V.
0.7V divided by Imax where Imax is the maximum current which gives the value of R6.
For example R6 is found to be 0.14Ω at Imax = 5A.
Since the loss of power might be significant at low output voltages and Imax equal currents so it is recommended that T1 and T2 transistors should be fitted with heatsinks.
Formula:
The transistor 2N3055 which can provide an output of 0-15V at up to 5A is usually found in a linear voltage regulator circuit to create a stabilized adjustable power supply.
The 2N3055 transistor controls the output voltage by acting as a pass element or power amplifier when combined with other components.
To configure Vout the output voltage is:
Vout = Vref (1 + R2 / R1)
where,
- The reference voltage or Vref is often set using a Zener diode or a stable voltage reference.
- The voltage divider network has resistors R1 and R2.
By connecting a current detecting resistor in line with the load and using the voltage drop across it one can control the base current of the 2N3055 transistor and so can limit the output current.
How to Build:
To build a Simple Stabilized Adjustable Power Supply 0-15V/5A Circuit follow the below mentioned connection steps:
Connection to the Circuit:
- Ground the LM317 input pin after connecting the input voltage source to it.
- Connect R1 between the LM317 output and adjustment pins.
- Connect R2 between the adjustment pin and ground.
- Connect P1 between the adjustment pin and ground.
- Connect C1 between the adjustment pin and ground.
- Connect C2 between the output pin and ground.
- Connect R3 between the LM317 output and the base of T1.
- Connect R4 between the base of T1 and ground.
- Connect T1collector to the output pin of the LM317 and connect T1 emitter to ground.
- Connect resistor R5 between transistor T1 collector and the base of T2.
- Connect T2 collector to the output pin of the LM317 and connect T2 emitter to ground.
- Connect C3 between the output pin of the LM317 and ground.
- Connect D1 between the output pin of the LM317 and the adjustment pin.
- Connect P2 in parallel with R5 to set the upper voltage limit.
- Calculate and install R6 based on the formula R6 = 0.7V / Imax.
- If using a lamp L connect it in parallel with the output to reduce power losses.
Testing and Modification:
- Turn ON the circuit and use a multimeter to measure the output voltage.
- To get the required voltage within the given range one should adjust P1 potentiometer.
- For choosing the top voltage limit such as 15 to 0V one should use P2 preset.
- Connect the right heat sinks to T1 and T2 transistors to provide adequate heat dissipation.
Precautions:
- Before turning ON the circuit verify every connections and component values.
- When conducting initial testing keep an eye on the circuit to spot any problems.
- Take the proper safety precautions such as being sure about the capacitors polarity is right and by preventing short circuits.
Conclusion:
This process is meant to be simple while working with electronics it is important to check the datasheets of individual components and follow to safety precautions.
If electronics are unfamiliar think about getting help from someone who knows more.
These power sources are frequently used in testing facilities, workshops and electronics labs where a steady and regulated power supply is needed for many different kinds of experiments like prototyping or powering electronic circuits while they are being developed.
Leave a Reply