Need a quiz buzzer - Page 3 - Electronic Circuits Projects Diagrams Free

clifweb · 2nd September 2006, 12:30 PM

Does someone know or think what is wrong with it.

philba · 4th September 2006, 06:07 AM

I only looked at it briefly but it seems to me that the idea is that the output of the LS30 will be low if no button is pressed and high if a button is pressed. this in turn is inverted by the LS00 which then is input to /LE on the LS373 and thus latching up the pressed button(s). so, I would follow those signals - pin 11 of the LS373 should be high when no buttons are pressed and then low when one has been pressed. If that's not the case, then trace the signal back. Based on your description, /LE is always high - I'd look at the LS30 and LS00 to see if they are properly connected.

Now, reset is a bit odd to me. pin 1 of the LS373 is output enable. pulled low, it enables output. pulled high, it puts the output pins in high impedence. I can only surmise that this is supposed to cause the LS30 to see high outputs from the LS373 and output a high which causes the state of the buttons to pass through the LS373. seems wrong to me. but presuming it can actually work that way, check that you have pins 1 and 11 of the LS373 properly wired - your schematic is unclear on that point.

Maybe a better solution for a reset is to use s1 to pull /LE high. this requires that no one is pushing any buttons. The LS373 will pass though the button signals (which are high), thus causing the LS30 to assert /LE high when s1 returns to the unpressed state. I'd use a resistor to ensure that you don't get a short circuit, though. debounce is a good idea but not really necessary, assuming that no one touches the buttons.

muki55 · 6th September 2006, 01:57 AM

Quote:

Originally Posted by clifweb

I found this buzzer and I thought that I should try it with ISIS 6 Professional before building it on a PCB. When I press the button the number stays the same. What is wrong and how to fix it. Since even in the schematic the data is not all readable. If some one could provide me with a better schematic it would be great even if the number of team would have to be less but I prefer it to be able to have 8 players/teams. The schematic was taken from http://www.electronic-circuits-diagr.../funckt2.shtml

Try this simply one an anti coincidence circuit.
Sorry for my drawing.
Diode is 1N4156
Hope that it will help you!!!!!!

philba · 6th September 2006, 04:08 AM

you sure about the lamps wired to the gate? the On Semi datasheet says gate current max is 50 mA.

muki55 · 6th September 2006, 05:41 AM

Quote:

Originally Posted by philba

you sure about the lamps wired to the gate? the On Semi datasheet says gate current max is 50 mA.

Yeah. You can try this with only 3 PUT, 3 push button, 1 diode, 3 lamps, 2 resistor and a 12vdc power supply and see for yourself how its works. enjoy your games

philba · 6th September 2006, 05:50 AM

If I were doing a quiz circuit, I certainly wouldn't do it that way - I'd use a uC. But I'm not. care to explain how it works?

Hero999 · 6th September 2006, 05:20 PM

That circuit won't work at all!
My guess is you've got the terminaly wrong on the diagram.

muki55 · 7th September 2006, 12:27 AM

Quote:

Originally Posted by Hero999

That circuit won't work at all!
My guess is you've got the terminaly wrong on the diagram.

Its really works. I do this circuit in vendo machine project. I replaced the lamp with homemade solenoid and win in the science fair.

Hero999 · 7th September 2006, 09:32 PM

Well I don't believe you!

Even though the schematic is worng you've probably built a totally different circuit.

philba · 7th September 2006, 10:16 PM

I'm still waiting for an explanation of how it works. In particular, what are the bulbs' wattage? At 12V, it would have to be 600 mW to avoid exceeding the gate max current from the datasheet. Pretty dim... And a solenoid??? seems pretty far fetched. I would think you got the gate and drain mixed up but am willing to listen to what you have to say (other than "it really works").

Come on, Muki, tell us why it "really works".

Hero999 · 8th September 2006, 03:31 PM

Perhapps it's just a lucky coincidence your anti-coincidence circuit worked.

philba · 8th September 2006, 03:44 PM

Quote:

Originally Posted by Hero999

Perhapps it's just a lucky your anit-coincidence circuit worked.

lol, I got it but you left out a word.

Hero999 · 8th September 2006, 04:27 PM

Fixed

muki55 · 10th September 2006, 03:59 PM

The circuit provides ground only to load selected first. Load that is driven desprives all others of triggering voltage to any number of load. The supply voltage is up to 50v and load current around 50mA

Hero999 · 11th September 2006, 09:08 PM

Rubbish!

How?

Please annotate your schematc and show us how it works.

The gates are all connected to +V via the bulbs ao they will burn out.

The switches are all connected in series with the cathodes.

The anodes are all connected to +V via 1k.

There is a circuit very similar to this that works. My guess is you've tried to draw it but got it wrong.

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2nd September 2006, 12:30 PM	(permalink)
clifweb	Does someone know or think what is wrong with it.

4th September 2006, 06:07 AM	(permalink)
philba	I only looked at it briefly but it seems to me that the idea is that the output of the LS30 will be low if no button is pressed and high if a button is pressed. this in turn is inverted by the LS00 which then is input to /LE on the LS373 and thus latching up the pressed button(s). so, I would follow those signals - pin 11 of the LS373 should be high when no buttons are pressed and then low when one has been pressed. If that's not the case, then trace the signal back. Based on your description, /LE is always high - I'd look at the LS30 and LS00 to see if they are properly connected. Now, reset is a bit odd to me. pin 1 of the LS373 is output enable. pulled low, it enables output. pulled high, it puts the output pins in high impedence. I can only surmise that this is supposed to cause the LS30 to see high outputs from the LS373 and output a high which causes the state of the buttons to pass through the LS373. seems wrong to me. but presuming it can actually work that way, check that you have pins 1 and 11 of the LS373 properly wired - your schematic is unclear on that point. Maybe a better solution for a reset is to use s1 to pull /LE high. this requires that no one is pushing any buttons. The LS373 will pass though the button signals (which are high), thus causing the LS30 to assert /LE high when s1 returns to the unpressed state. I'd use a resistor to ensure that you don't get a short circuit, though. debounce is a good idea but not really necessary, assuming that no one touches the buttons.

6th September 2006, 04:08 AM	(permalink)
philba	you sure about the lamps wired to the gate? the On Semi datasheet says gate current max is 50 mA. Last edited by philba; 6th September 2006 at 04:41 AM.

6th September 2006, 05:50 AM	(permalink)
philba	If I were doing a quiz circuit, I certainly wouldn't do it that way - I'd use a uC. But I'm not. care to explain how it works?

6th September 2006, 05:20 PM	(permalink)
Hero999	That circuit won't work at all! My guess is you've got the terminaly wrong on the diagram. __________________ I also post at the following sites: http://www.stop-microsoft.org http://www.heated-debates.com Screen name: Aloone_Jonez

7th September 2006, 09:32 PM	(permalink)
Hero999	Well I don't believe you! Even though the schematic is worng you've probably built a totally different circuit. __________________ I also post at the following sites: http://www.stop-microsoft.org http://www.heated-debates.com Screen name: Aloone_Jonez

7th September 2006, 10:16 PM	(permalink)
philba	I'm still waiting for an explanation of how it works. In particular, what are the bulbs' wattage? At 12V, it would have to be 600 mW to avoid exceeding the gate max current from the datasheet. Pretty dim... And a solenoid??? seems pretty far fetched. I would think you got the gate and drain mixed up but am willing to listen to what you have to say (other than "it really works"). Come on, Muki, tell us why it "really works".

8th September 2006, 03:31 PM	(permalink)
Hero999	Perhapps it's just a lucky coincidence your anti-coincidence circuit worked. __________________ I also post at the following sites: http://www.stop-microsoft.org http://www.heated-debates.com Screen name: Aloone_Jonez Last edited by Hero999; 8th September 2006 at 04:26 PM.

8th September 2006, 04:27 PM	(permalink)
Hero999	Fixed __________________ I also post at the following sites: http://www.stop-microsoft.org http://www.heated-debates.com Screen name: Aloone_Jonez

10th September 2006, 03:59 PM	(permalink)
muki55	The circuit provides ground only to load selected first. Load that is driven desprives all others of triggering voltage to any number of load. The supply voltage is up to 50v and load current around 50mA

11th September 2006, 09:08 PM	(permalink)
Hero999	Rubbish! How? Please annotate your schematc and show us how it works. The gates are all connected to +V via the bulbs ao they will burn out. The switches are all connected in series with the cathodes. The anodes are all connected to +V via 1k. There is a circuit very similar to this that works. My guess is you've tried to draw it but got it wrong. __________________ I also post at the following sites: http://www.stop-microsoft.org http://www.heated-debates.com Screen name: Aloone_Jonez