ultra Posted October 21, 2007 Report Share Posted October 21, 2007 hi,i've made a circuit off a schematic i found on the web that will let me use a tact switch as a power toggle. However, when the circuit is off, there is a constant .6V to the load (when using a 9V battery). will this create a problem with the core, or will it work as if it's shut off?thanks!ultra Quote Link to comment Share on other sites More sharing options...
doc Posted October 21, 2007 Report Share Posted October 21, 2007 Hi,there are many possibilities to use a tact switch as a power toggle. The easiest is a transistor, 2 caps and two resistors ... I don't know yours, but:0.6V to the core isn't really a problem. It will work as if it's shut off. No problem there.Please pay attention on the current your "power off" switch must handle! (As said before, I don't know your circuit).greetsDoc Quote Link to comment Share on other sites More sharing options...
ultra Posted October 21, 2007 Author Report Share Posted October 21, 2007 hi,i connected an ammeter. i'm using a 9v battery and led to test this circuit, the led pulls about 7.6mA when the circuit is on, and about 15uA when the circuit is off. that is a standard led and 1K resistor as the load.it works very well. the only thing is when you initially give it power (say plug your adapter into the wall), the circuit will be on. but it stays off once you shut it off. with the mosfet i used, i can pull up to 4A, so plenty for the seq. i'm going to go ahead and use this circuit for my seq. Quote Link to comment Share on other sites More sharing options...
doc Posted October 22, 2007 Report Share Posted October 22, 2007 ok, now it's getting clearer.With the mosfet as driver you won't run in any power problem. The small amount of voltage you have after power off is normal in this circuit.If you want to make it absolute sure, you can use a solid state relais as load to switch your seq on and off. Doing this, you also have no problem with the different levels (+9 -18 V versus +5V for Core).If you drive this circuit with 5V, you have to change some resistor values, I guess.greetsDoc Quote Link to comment Share on other sites More sharing options...
stryd_one Posted October 22, 2007 Report Share Posted October 22, 2007 Off topic, this is what's cool about DIY. You've gone to this trouble to make this cool addon, which makes power switching easier, while I went and bought switch guards to do the opposite. Love it ;DDamn my infernal brain... I just got to thinking how cool it would be to have this circuit with a timer so you have to hold the switch in for a few seconds... I don't want to hijack, but I'm curious if anyone would know how to do this? Should I start a new thread guys? Quote Link to comment Share on other sites More sharing options...
/tilted/ Posted October 22, 2007 Report Share Posted October 22, 2007 that's ok Stryd, I remember that from the chat room. I think a good old NE555 would work well for that. Quote Link to comment Share on other sites More sharing options...
ultra Posted October 22, 2007 Author Report Share Posted October 22, 2007 stryd, we can keep that in this thread.the schematic with description is found here:http://ourworld.compuserve.com/homepages/Bill_Bowden/page9.htmhe mentions changing values of some components to change charge time, and i will for sure be experimenting with that before i make this circuit final. also, i noticed he mentioned something about power-on state, meaning i can probably also modify it so there's no power when i first plug it in. either way, the seq is getting a master power switch at the back.edit: my ee instructor said something about RC time constant. i guess resistance and capacitance amounts will change the amount of time it takes a cap to charge. god i love learning this stuff :). Quote Link to comment Share on other sites More sharing options...
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