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Hello, I would like to control three 5-6 V DC motors using the BX24. Of course, the motors can not be directly connected to the the BasicX 24 chip since it is not designed for that sort of current. What relays or MOSFETS (or anything else) would you recommend for this task?

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Or maybe I should use transistors or the ULN2003AN? Thanks

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Mosfet IRL520N (from International Rectifier). Works well in the applications we use it for. Harry -----Original Message----- From: koganrvss [mailto:] Sent: Friday, May 16, 2003 11:20 PM To: Subject: [BasicX] Connecting Relays and MOSFETS Hello, I would like to control three 5-6 V DC motors using the BX24. Of course, the motors can not be directly connected to the the BasicX 24 chip since it is not designed for that sort of current. What relays or MOSFETS (or anything else) would you recommend for this task? [Non-text portions of this message have been removed]

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How much current will the motors pull? If they arevonly a few hundred milliamps, you could use a ULN2003, a UCN5821, a small relay or a transistor or a power fet. All will work. Just depends on what is easdier for you. Do you need help onn how to connect them? All options will need a flywheel diode accross the motor. koganrvss wrote: > Or maybe I should use transistors or the ULN2003AN? > > Thanks > Yahoo! Groups Sponsor ADVERTISEMENT [Click Here!] > Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service. [Non-text portions of this message have been removed]

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Thanks for your reply. I bought a couple of ULN2003As yesterday. The manual states: "All devices feature open-collector outputs with integral clamp diodes. " Would I need to add additional diodes? As far as I understand, the diode is there to block reverse voltage from the motor. There are many kinds of diodes, what are the important characteristics of a flywheel diode? --- In , Neil Jepsen <njepsen@i...> wrote: > How much current will the motors pull? If they arevonly a few hundred > milliamps, you could use a ULN2003, a UCN5821, a small relay or a > transistor or a power fet. All will work. Just depends on what is > easdier for you. > Do you need help onn how to connect them? All options will need a > flywheel diode accross the motor. > koganrvss wrote: > > > Or maybe I should use transistors or the ULN2003AN? > > > > Thanks

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You are correct, the ULN has the flywheel diodes internally connected PROVIDED you connect the power supply you are using for the motors to the terminal on the ULN marked COM (pin 9). A flywheel diode must be able to handle the current and voltage that the motor is capable of generating when its supply is suddenly turned off ... called back emf. It is usually at least 4 or 5 times higher than the voltage of the motor and the current can be a lot higher than that which the motor draws normally. In the case of small relays motors and other inductive loads running at up to 24v DV, a 1N4003 is OK. 300volt 1A diode. You should alsways use a flywheel diode when you are switching an inductive load. neil koganrvss wrote: > Thanks for your reply. > I bought a couple of ULN2003As yesterday. > The manual states: "All devices feature open-collector outputs with > integral clamp diodes. " > > Would I need to add additional diodes? > As far as I understand, the diode is there to block reverse voltage > from the motor. There are many kinds of diodes, what are the > important characteristics of a flywheel diode? > > --- In , Neil Jepsen <njepsen@i...> wrote: > > How much current will the motors pull? If they arevonly a few > hundred > > milliamps, you could use a ULN2003, a UCN5821, a small relay or a > > transistor or a power fet. All will work. Just depends on what is > > easdier for you. > > Do you need help onn how to connect them? All options will need a > > flywheel diode accross the motor. > > koganrvss wrote: > > > > > Or maybe I should use transistors or the ULN2003AN? > > > > > > Thanks > Yahoo! Groups Sponsor ADVERTISEMENT [Click Here!] > Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service. [Non-text portions of this message have been removed]

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