Control a car toy. The toy car is controlled via a controller that is connected to it via a wire, so it`s not radio controlled. I would like to use relays to control toy via parallel port. I think there are many relay types and models, and I would like to know which one is the most suitable one for this case. [ I never used relays before] Also, I may try to use the parallel port to control a desk lamp that runs on AC power,
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so I need the model number of a relay that can be used in this case [any circuit schematic would be appreciated too Note: In my country, it is very hard to get electronic components, and getting them online is not an available option for me, so can you please give me more than one model number of relays that can do the thing I need The parallel port will not directly drive relays (0V and ~3. 5V). Your best bet is to use an external power supply (12 or 24V to match commonly available relays) and use a NPN switching transistor to drive the relay coil. Use a 1K resistor between the parallel port pin and the base of the transistor. Use a silicon rectifier (1N400x type) as a snubber across the relay coil; anode to collector, cathode to V+. This way you should be able to use commonly available automotive 12V relays. This link is very good to get you started using the parallel port and shows exactly what MikeMI was getting at using transistors. The link also has dozens of other useful links. Additionally this other link is for a relay card designed for parallel port operation. The nice thing is they give a link to their board showing the circuit in schematic form. Also very good is a link to their software for controlling a parallel port. Something I noticed is the above software will run on Windows XP and earlier Microsoft operating systems as well as Linux. Newer systems like Vista and Windows 7 don`t run it. Thanks for...
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