Tech21 Triac alike swithcing schem

[wui223]

Does anyone has idea how the switching system of Tri-Ac ?
I want to have something like this: three different modes, press button 1 enable mode 1 and etc. Once a button pressed, previous mode is disabled. Include an all-bypass button to bypass whole effect.
Is it possible to have a programmed feature like Tri-Ac to store up different setting for each mode>?

[Peter Snowberg]

R.G. has a control article that covers switching like that over at GEO.

I'm in a rush now, but look at this datasheet: http://www.semiconductors.philips.com/acrobat_download/datasheets/74HC_HCT74_3.pdf

If you get two 74HCT74 dual flip-flops and you wire up the SET and RESET lines to the switches using 1N4148 signal diodes to "share" the switch between three individual flip-flop circuits, you can easily get the job done in a small space at very low cost.

Each flip-flop has a SET line which when transitioned from low to high, will set the output (Q) to high. When the RESET line is taken from low to high it will make the output (Q) low. It's not triggered by being low or high, but by the switch from low to high.

Put a pull-down resistor on each SET and RESET line of something like 10 or 22K. Now wire a momentary switch from power. Take the other side of the switch and connect it to the anodes of three diodes. Connect each cathode to the RESET lines of three flip-flops. That switch is now your "CLEAR" switch. The pull-downs keep the reset lines ready to go and the switch provides the low to high transition. For the "channel 1" switch, connect it the same way with three diodes, but connect the SET line of flip-flip #1 and the RESET lines of flip-flops #2 and #3. For the channel 2 switch, connect the SET line of #2 and the RESET lines of #1, and #3. With the third the same way.

Parts list:
Momentary SPST switches   (Quan. 4)
74HTC74  (Quan. 2)
22K resistors    (quan. 6)
1N914/1N4148 signal diodes    (Quan. 12)

That's it.

You are now left with three logic outputs that can be used for CMOS switching directly, or you can use any general purpose transistor to switch a small relay for true-bypass switching of components or signals.

[wui223]

Thanks for ur informative reply i will take some time to figure out the whole things. Thanks again. In fact i am thinking of building a GT2 with just the Amp selection or the mods maybe. But giving individual EG for each mode. So i can have 3 different setting for 3 modes.

[Nikolay]

Peter, can you draw some scheme with 74hc74?
Thanks

[wui223]

Seems like well beyond my capability to figure out the schematic but i get the rough idea. If schematic is available that will be nice.

PS: A picture means thousands words