coloradoxc
- Jun 28, 2011
- 4
- Joined
- Jun 28, 2011
- Messages
- 4
Hello. I am having trouble figuring out how to select the right type of transistor for a project I am working on. The project involves running a small pump (link below) off a rechargable lead acid battery. The pump will be connected to a filter sampler and must be able to run continuously for 5 hours minimum. The pump will be connected to a 555 circuit that will allow the flow rate of the pump to be adjusted using a potentiometer that changes the on/off Duty cycle, not the frequency. My problem, the NE555 chip I used can only output a maximum of 250 mA of current, with a max voltage of 15 V. The pump below requires at standard operating conditions 1A at 12 V with a 12 Watt power dissapation. I assume that when I adjust the on duty cycle to less than 50% I could be expected higher currents, double, tripple? What kind of transistor should I use to amplify the current without wasting to much energy to heat, and work within those regions. I got the circuit to work with a different pump (Hoover hanyvac motor) using a IRFZ46N mosfet, but it generates a lot of heat. Any ideas. Thanks a lot. I don't have any other information on the pump since I'm still waiting on the shipment. Also, the dc signal is curertly set to oscillate at 130 Hz. (Changable if necessary)
http://www.datasheetcatalog.org/datasheet/philips/NE_SA_SE555_C_2.pdf
http://www.sparkfun.com/datasheets/Robotics/Other/spec sheet.jpeg
http://www.datasheetcatalog.org/datasheet/philips/NE_SA_SE555_C_2.pdf
http://www.sparkfun.com/datasheets/Robotics/Other/spec sheet.jpeg