A Practical O~30V Adjustable Regulated Power Supply with Excellent Performance
Output Regulation Guaranteed
The output of this power supply is regulated by two stages and three terminals, so it can get good voltage stability (not inferior to ± 0.5%). The output adjustable voltage of 1.25 ~ 35V passes through D6, D and BG: The 2.8v threshold voltage formed by the two BE junctions can realize the continuous adjustment of 0~32V at the output end of the power supply. Because the Darlington tube BG is connected in the form of an emitter follower, the current required for the three-terminal output of the LM317 is very small, ensuring a constant output voltage of the power supply.
reliable protection
When a short circuit occurs at the output terminal, BG is in a saturated state, and its protection resistor bears all the saturation voltage drop. The voltage between A and B drops rapidly to 40V or below, BGi is cut off, the two ends of the relay J_excitation coil are released due to the lack of 24V excitation voltage, J is disconnected, and the T-transformer is powered off once, and D indicates The light-emitting tube goes out, the whole machine stops working, and the short-circuit protection action is completed. In the same way, when the voltage at both ends of A and B is <40V, the protection circuit operates, BG- is cut off, Jl is released, and the whole machine also stops working, realizing the over-current protection action. If you want to restart the power supply, you need to release the short circuit state, press the reset button to restart the whole machine. . The instrument completes the overcurrent protection and short circuit protection with the same protection circuit, which realizes the ultimate protection control and provides a strong guarantee for the reliable operation of the whole machine.
The long-term use of this power supply in our actual work has proved that it has stable performance, high reliability, easy operation and strong practicability. In addition to being suitable for the research and development of general electronic products, under the condition of small load. It can also provide a stable voltage source for precision instrument calibration. Here, the power supply can also be extended to four independent outputs (4 sets of secondary windings are wound on the auxiliary end of the transformer), and various independent outputs such as 0~60V, 0-120V, ±30v, and ~60V can be easily obtained. This kind of power supply expands the application occasions of the power supply.
