Please somebody help!
I'm not really an electronics guy, but I'm trying to learn. I'm working on a project making heated clothing for use in the cold Ohio weather. The heater will be powered with the motorcycle battery. So far, I've had success using a Velleman MK111 timer, modified with the supplied relay driving a 12 volt 30 amp automotive type relay. The heater circuit needs too much current to use the Velleman relay by itself. All is well and good except for one thing: The package is too big. My idea is to eliminate the Velleman relay and use a transistor in its place, thereby reducing the size of the package. I got a TIP3055 NPN transistor from Radio Shack thinking I could use it. So far, I've studied diagrams and made calculations on Excel for a week or so, but I'm still confused. I just don't know enough. I plan on wiring the circuit in common emitter mode (www.kpsec.com). The relay I want to drive has a resistance of 41.6 ohms. The input to the Velleman circuit is directly from the motorcycle battery. I have gloves hooked up drawing .5 ohm resistance. The wire in the gloves is 10 feet total of 30 AWG teflon coated copper. As a side note, 30 feet of the wire works fine connected directly to the battery, with no timer or other controls. I'm using the timer for just the gloves, or any future circuit with resistance too low to dissipate the heat. My questions - 1)Can I use the TIP3055? 2)What should the Base resistor be? 3)What am I overlooking? Thanks much.
I'm not really an electronics guy, but I'm trying to learn. I'm working on a project making heated clothing for use in the cold Ohio weather. The heater will be powered with the motorcycle battery. So far, I've had success using a Velleman MK111 timer, modified with the supplied relay driving a 12 volt 30 amp automotive type relay. The heater circuit needs too much current to use the Velleman relay by itself. All is well and good except for one thing: The package is too big. My idea is to eliminate the Velleman relay and use a transistor in its place, thereby reducing the size of the package. I got a TIP3055 NPN transistor from Radio Shack thinking I could use it. So far, I've studied diagrams and made calculations on Excel for a week or so, but I'm still confused. I just don't know enough. I plan on wiring the circuit in common emitter mode (www.kpsec.com). The relay I want to drive has a resistance of 41.6 ohms. The input to the Velleman circuit is directly from the motorcycle battery. I have gloves hooked up drawing .5 ohm resistance. The wire in the gloves is 10 feet total of 30 AWG teflon coated copper. As a side note, 30 feet of the wire works fine connected directly to the battery, with no timer or other controls. I'm using the timer for just the gloves, or any future circuit with resistance too low to dissipate the heat. My questions - 1)Can I use the TIP3055? 2)What should the Base resistor be? 3)What am I overlooking? Thanks much.
