On 2/18/10, Joep Suijs <[email protected]> wrote: > > Hi Guys, > > For an car application, I need to toggle power supply (12v) with a > momentary push-button. Someone mentions a bistable relay, but the only > one I see (at conrad.nl) are one's with two coils and I can't think > how to create this toggle function. > > Any ideas? > > Or do I need something like a D-flipflop to achieve this?
You can do it with a D flipflop made from two nand gates if the push has both NO-NC contacts or if you have only NO contact try this one (I use it in a frequency meter design when I was in highschool, 30 years ago) Recipe: 1/2 of 474 or equivalent 1 inverter gate 404 or equivalent 1 capacitor 100nF to 1uF 1 resistor 330 ohm to 1K 1 pushbutton with 1k pullup Mixt togheter in a blender like this: - connect the inverter output to bistable NOT R input - connect capacitor from NOT Q bistable output to inverter input - connect resistor from Q bistable output to inverter input - connect pushbutton between NOT S input to GND,1K resitor to VCC If use CMOS version and increase all R values you can supply all stuff from 12V. This circuit is the most stable I saw over the years for such application. Vasile -- You received this message because you are subscribed to the Google Groups "jallib" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/jallib?hl=en.
