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Circuit Problem!!!

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semajholland said:
I know a 555 IC isn't a transistor, i meant the transistor by the 555 chip. (Learn to read HiTech!!!!!) It's un-named. I wanted to know if i could put any old npn in it's place.Great help, Thanks.
Since you are constructing one of Bill Bowden's circuits, why didn't you bother to email the man himself with your questions, which by the way his addy was very easy to locate and is published for such reasons as yours! And so you don't develop severe astigmatism after hours of surfing for Mr. Bowden's email addy., I have done the work for you!
76606.611@compuserve.com

Yes, it really is Mr. Bowden's address.

:p
 
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oldtimer said:
They cetainly can,and do,but this is an electronics talk site.Get the idea.
Well, oldtimer, I'll come to your defense. You said:
I think you ought to take that silly comment out, it makes you out a moron.
I don't see any hint of Fascism there - just a personal opinion. I also tend to think HiTech's signature is a little silly, but no worse than mine. :(
 
Ron H said:
The base of the 2N3906 is driven by the Carry Out pin of the counter. The Sziklai circuit is just a high gain emitter follower. High beta will not cause it to respond unpredictably, unless it happens to oscillate, which in my experience is only likely when both transistors have similar Ft's (transition frequencies).

Yes, of course, I agree.

But, in your opinion, what is causing the relay to turn on? According to the schematic the relay was to pulse, in a 8-second inteval.

I can only think about these things:
1 - The transistor pair has none resistor in base.
2 - The Carry Out pin "high-level output voltage" is too low, causing the transistor pair to conduct.
3 - The RESET pin is draining too much current, causing a voltage loss on the Carry Out pin "high-level output voltage", making the the transistor pair conduct.
4 - The Carry Out pin is not supplying current enough to the RESET pin, causing a voltage loss.
 
oldtimer said:
The 555 is an astable which pulses at a 1 second rate, the pulses are fed into the 4518 counter and when pin 7 goes low the relay is energised. The 4011 is a quad 2 input nand gate and is used to forwrd bias each diode or combination to display the pulse count..Any general purpose transistor will do in the 555 circuit.
Oops, Not often I'm right but wrong again,it is a 4511 and not a 4011 a 4000 series cmos chip as described elsewhere.
 
Ron H said:
Well, oldtimer, I'll come to your defense. You said:
I don't see any hint of Fascism there - just a personal opinion. I also tend to think HiTech's signature is a little silly, but no worse than mine. :(
Agreed! There are better things for people to get uptight over. BTW I had to take a second look at your location -- LOL clever. Almost has a radical, militant Islamic ring to it!!
 
Hayato said:
Yes, of course, I agree.

But, in your opinion, what is causing the relay to turn on? According to the schematic the relay was to pulse, in a 8-second inteval.

I can only think about these things:
1 - The transistor pair has none resistor in base.
2 - The Carry Out pin "high-level output voltage" is too low, causing the transistor pair to conduct.
3 - The RESET pin is draining too much current, causing a voltage loss on the Carry Out pin "high-level output voltage", making the the transistor pair conduct.
4 - The Carry Out pin is not supplying current enough to the RESET pin, causing a voltage loss.
Semajholland said:
The output of the 555 is held high by the switch when it's off. But flick the switch and the out put goes low but stays low. No pulsing. I noticed the discharge wasn't connected into the circuit is this essential for correct operation.
Later he said:
When i test the output of the timer, sometimes it pulses at 1 second intervals and sometimes it doesn't. Loose connection?
I wonder if he has a floating input pin(s) on the counter. I also wonder if he is using a normally-closed toggle switch, (accounting for the 555 being normally high), when he should be using a normally-open momentary-contact switch.
 
HiTech said:
Agreed! There are better things for people to get uptight over. BTW I had to take a second look at your location -- LOL clever. Almost has a radical, militant Islamic ring to it!!
I hate the way this board drops nested quotes, which sometimes totally changes the meaning, as in your last post.
I think my "location" is something I got from Al Capp's Li'l Abner comic strip in days of yore. Or maybe not. Wherever I got it, I think I may have morphed it somewhat from the original.
 
or perhaps... "take your time with anal" :rolleyes: :eek:
 
Semi success....finaly?

I have built this circuit and I am currently testing it.
What I got so far was the display showed 0 started at 9 went back to 0.
I also tried taking pin 4 from 7 it did some thing weired counted like it was supposed to for 2sec and displayed a backwards 6.
Also when pin 4 is hooked to pin 7 the 555 circuit only counts once when its not connected every second how I know I taped pin 3 of the 555 Timer to a led to see the pulses.
 
Hi TechnoGeek-119,

TechnoGeek-119 said:
I also tried taking pin 4 from 7 it did some thing weired counted like
it was supposed to for 2sec and displayed a backwards 6.
Also when pin 4 is hooked to pin 7 the 555 circuit only counts once
when its not connected every second how I know I taped pin 3 of
the 555 Timer to a led to see the pulses.

You can't see what's happening by connecting a led to the output
of the timer, it can only be displayed on a storage oscilloscope.
Pin 4 of the timer is the reset pin, it should never be left open.
Either you connect it to gnd and the timer will remain in it's reset
position or you connect it to Vcc and then it will oscillate indefinately
and the circuit will count down from 9 to 0 again and again. And each
time the counter jumps to zero the relay will pull in for about a half
clock pulse.
Also replace the relay driver, the circuit is already ridiculous enough
as it is now.

on1aag.
 

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i want to know complete information about LM 393 IC in a vehicle loop detector... :confused:
This is the fourth of 4 posts asking the same question, within 40 minutes.

If you post your question 4 times you will not get 4 answers; more likely none. :mad:
 
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