Timer-Controlled 5 A Constant Current Source
Thapalia, Pratyush (2021)
Thapalia, Pratyush
2021
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Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi:amk-202104195072
https://urn.fi/URN:NBN:fi:amk-202104195072
Tiivistelmä
The main objective of this project was to build a constant current source with a 5 A output. The project expectation was to create a power source capable of delivering high current output, generating the necessary thermal power to sever medical suture lines. As an end de-vice, loads of the order of 0.5-1 ohm were used. The target was to heat the load and produce high thermal power at the designated part of the load.
The main components used in this adjustable current source are LM317, a 3-Terminal Adjustable Regulator alongside transistors 2N3055 and 2N2905. LM317 voltage regulator is used to converting the rectified DC voltage to a constant output voltage which is used to produce high thermal power at the load provided and is connected to a PWM circuit for a power cut-off ranging from 1 to 10 seconds. An enclosed 120 W industrial single output switching power supply adopting the full range of 85-264 VAC input, providing the output of 12 VDC, and the current range of 0-10 A is used for the connection with the AC mains, be-cause of its complete protection function as the design is intended for being used in the medical department.
The project was first allocated into small individual tasks, in particular the delivery of constant steady output current, creating a cut-off PWM. Firstly, all the prototypes were designed in the Multisim, a circuit simulator software for the verification, and then tested on the breadboard. The PCBs were then designed through the PADS software package and all the components were mounted and soldered. Lastly, the circuit and the cooling devices were mounted in a plastic enclosure box for the safety precautions and possible contaminations as being used in medical facilities.
The main components used in this adjustable current source are LM317, a 3-Terminal Adjustable Regulator alongside transistors 2N3055 and 2N2905. LM317 voltage regulator is used to converting the rectified DC voltage to a constant output voltage which is used to produce high thermal power at the load provided and is connected to a PWM circuit for a power cut-off ranging from 1 to 10 seconds. An enclosed 120 W industrial single output switching power supply adopting the full range of 85-264 VAC input, providing the output of 12 VDC, and the current range of 0-10 A is used for the connection with the AC mains, be-cause of its complete protection function as the design is intended for being used in the medical department.
The project was first allocated into small individual tasks, in particular the delivery of constant steady output current, creating a cut-off PWM. Firstly, all the prototypes were designed in the Multisim, a circuit simulator software for the verification, and then tested on the breadboard. The PCBs were then designed through the PADS software package and all the components were mounted and soldered. Lastly, the circuit and the cooling devices were mounted in a plastic enclosure box for the safety precautions and possible contaminations as being used in medical facilities.