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help with transistors

could someone tell me if this will succeed in keeping itself on if the button is hit once?

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VIRON10 years ago
This may work, simply, much like like an SCR.
latchlite.jpg
VIRON VIRON9 years ago
This is tested, tweaked, and now it works. Needed 10K resistors to help it.
latcher.jpg
James (pseudo-geek) (author)  VIRON9 years ago
for everyone reading, the above shematic is the correct one, and will work under slight variations fro mthe original schematic.
James (pseudo-geek) (author)  VIRON9 years ago
ok I'll try this one, I'm quite sure it will work (since you tested it).
WOOT IT WORKS! *E-hug* tytytytyty except the off switch turns it on and the on switch turns it off so I just reversed them heh. thanks again.
James (pseudo-geek) (author)  VIRON10 years ago
could you please clarify the B,C and E of those transistors?
One is NPN, one is PNP, and I use (lots of) 2N3904 and 2N3906 which are typical small transistors about 1/2 watt. In UK the equivalents start with "BC" and in Japan, "2S", with different numbers found using a "cross-reference" book or search. If they are black plastic, and viewed from above with the flat side facing right, or from the bottom with flat facing right, the top pin is C, the middle B, and the bottom E. In schematics E has the arrow and B is straight from the middle. Various other transistors have pins in BCE or reverse order, you have to test them or look them up to know. The "diode" is an LED. I changed my idea; don't use the 1K resistor, but it might be necessary to use a 10K from there to the negative for the "off" button to work. BTW the one "transistor" circuits might work if you use an SCR or TRIAC which can be found in small lamp dimmers as the transistor. They don't "dim" DC, but they do latch on when you push a button in a DC circuit. They also handle lamps up to and over 100 watts.
James (pseudo-geek) (author)  VIRON10 years ago
thanks a ton, I'll try it.
didnt work.
westfw10 years ago
Here is a pdf containing your basic two-transistor bistable circuits to implement a set/reset latch, a monostable (pulse) circuit, and an oscillator (which happens to be the same as my Instructable on PCB DRCs, although that's not specifically what it was about.)
Somewhat more complex but essentially similar circuits make up MANY a standard Integrated Circuit, from 555s to flipflops to registers and static RAM.
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