Need a quiz buzzer - Page 4 - Electronic Circuits Projects Diagrams Free

muki55 · 12th September 2006, 01:10 AM

Quote:

Originally Posted by 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.

The circuit is a simple relaxation type oscillator . The Programmable Unijuntion Transistor (PUT) in a blocking state conducts. When its gate is made negative relative to its anode. This task of switching is accomplished by the resistor 1K.

Hero999 · 12th September 2006, 11:05 PM

You're still wrong.

Those symbols aren't programmable unijunction transistors, they're thyristors/SCRs!

Even if you replaced them with programmable unijunction transistors, it still wouldn't work as a relaxation ocsillator since there are no timing capacitors which are required in all relaxation oscillators!

jace33 · 12th September 2006, 11:31 PM

ANTI COINCIDENCE CIRCUIT

Ok guys anoth of the crap i have just built this circut not using eight players but made a three player one and this circut dosnt work. Have tried to rebuild it and it dosnt work does anyone out there know of a 12 volt simple circute that is a quizz master I am running out of time and need to make one with in two weeks as triva nights are starting back.

thanks

philba · 13th September 2006, 12:15 AM

which circuit did you build? the PUT one that muki posted? that one will never work.

use the one from the first page. I think the reset mod I suggested will work fine.

audioguru · 13th September 2006, 12:25 AM

Geez, I haven't seen a PUT for over 30 years.
Muki got the symbol correct, but his circuit won't work.

A PUT works as an oscillator by having the charging capacitor at its Anode, making a trigger voltage reference with a voltage divider at its Gate, and having the load to ground at its Kathode (spelling mistake because it is K).
When the capacitor's charging voltage at the Anode is a little higher than the gate voltage then the PUT conducts the capacitor's charge into the load.

musthave · 13th September 2006, 12:34 AM

here is a quiz master from 1991 PE hobbyist handbook

jace33 · 13th September 2006, 01:36 AM

oK GUYS no more fighting what i have and wanted to achieve with this circut is as follows. i have made two boxes up each with three push buttons and three 12 volt round trailer lights you buy from the auto car shop the aim of the thing is to sit the boxes on a table and ask people questions and the first one in that presses their button their light comes on blocking everyone elses is there a simple circut out there if so can someone let me know please. Should of saw me last night when i couldnt get the thing to work not a happy camper lol anyway guys if some one can help me out thanks

Hero999 · 15th September 2006, 03:04 PM

Quote:

Originally Posted by audioguru

Geez, I haven't seen a PUT for over 30 years.
Muki got the symbol correct, but his circuit won't work.

A PUT works as an oscillator by having the charging capacitor at its Anode, making a trigger voltage reference with a voltage divider at its Gate, and having the load to ground at its Kathode (spelling mistake because it is K).
When the capacitor's charging voltage at the Anode is a little higher than the gate voltage then the PUT conducts the capacitor's charge into the load.

You're right, after logging off I looked it up on the Internet and understand PUTs now. In a way, a PUT is like an SCR but it triggers when the gate is above the anode instead of below the cathode voltage.

In theory you can make a priority quiz indicator with PUTs and I know this isn't the way to do it, but I don't see why anyone would bother when SCRs are so much easier to get hold off.

Quote:

Originally Posted by musthave

here is a quiz master from 1991 PE hobbyist handbook

Good, but a schematic is useless without a bill of materials.

jace33 · 16th September 2006, 12:23 PM

so does Muki circuit works or not
if it dosnt work what adjustments must be made to make it work

Hero999 · 16th September 2006, 09:04 PM

I haven't tested this but it should work.

jace33 · 19th September 2006, 01:44 PM

ok so this circuit you have just done up should work as quiz light thing blocking out everyone else that didnt press their button first etc.. and why is the first light mising a switch or is that just a light for the power on etc..

thanks

**Nigel Goodwin** · 19th September 2006, 01:50 PM

Quote:

Originally Posted by jace33

and why is the first light mising a switch or is that just a light for the power on etc..

There's a technical term for it - "MISTAKE"

Hero999 · 19th September 2006, 06:18 PM

Obviously. I've corrected it now.

muki55 · 21st September 2006, 04:00 AM

My circuit works so far.

musthave · 22nd September 2006, 12:38 AM

Here is the parts list I was waiting to see if you where interested in this circuit but never got an email to the post, so I tough it was dead post.

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12th September 2006, 11:05 PM	(permalink)
Hero999	You're still wrong. Those symbols aren't programmable unijunction transistors, they're thyristors/SCRs! Even if you replaced them with programmable unijunction transistors, it still wouldn't work as a relaxation ocsillator since there are no timing capacitors which are required in all relaxation oscillators! __________________ I also post at the following sites: http://www.stop-microsoft.org http://www.heated-debates.com Screen name: Aloone_Jonez And http://www.silicontronics.com, same screen name as here.

12th September 2006, 11:31 PM	(permalink)
jace33	ANTI COINCIDENCE CIRCUIT Ok guys anoth of the crap i have just built this circut not using eight players but made a three player one and this circut dosnt work. Have tried to rebuild it and it dosnt work does anyone out there know of a 12 volt simple circute that is a quizz master I am running out of time and need to make one with in two weeks as triva nights are starting back. thanks

13th September 2006, 12:15 AM	(permalink)
philba	which circuit did you build? the PUT one that muki posted? that one will never work. use the one from the first page. I think the reset mod I suggested will work fine.

13th September 2006, 01:36 AM	(permalink)
jace33	oK GUYS no more fighting what i have and wanted to achieve with this circut is as follows. i have made two boxes up each with three push buttons and three 12 volt round trailer lights you buy from the auto car shop the aim of the thing is to sit the boxes on a table and ask people questions and the first one in that presses their button their light comes on blocking everyone elses is there a simple circut out there if so can someone let me know please. Should of saw me last night when i couldnt get the thing to work not a happy camper lol anyway guys if some one can help me out thanks

16th September 2006, 12:23 PM	(permalink)
jace33	so does Muki circuit works or not if it dosnt work what adjustments must be made to make it work

19th September 2006, 01:44 PM	(permalink)
jace33	ok so this circuit you have just done up should work as quiz light thing blocking out everyone else that didnt press their button first etc.. and why is the first light mising a switch or is that just a light for the power on etc.. thanks

19th September 2006, 06:18 PM	(permalink)
Hero999	Obviously. I've corrected it now. __________________ I also post at the following sites: http://www.stop-microsoft.org http://www.heated-debates.com Screen name: Aloone_Jonez And http://www.silicontronics.com, same screen name as here.

21st September 2006, 04:00 AM	(permalink)
muki55	My circuit works so far. Last edited by muki55; 21st September 2006 at 04:08 AM.