91xr7
Junior Member
Posts: 51
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Post by 91xr7 on Sept 4, 2014 20:26:49 GMT -8
Just wondering if this forum is for this site or for Help in electronics General? Since i Kinda need help with a Timing circuit i made using a NE556 IC Now what i like to try and figure out is how to get the Delayed On circuit to reset without shutting down the Delayed off circuit? Basics: The Delayed On Circuit just delays output #2 from triggering at the same time as #1 The Delayed Off Circuit just keeps output #3 running for awhile after Input 1 shuts off Input 1 is "low" Input 2 is "low" All Outputs go to 85ohm relays What i would like to know is how do I modify the the Delay on circuit so it's Triggered by what's happening on Input #1? when input 1 is grounded the timer starts, when the ground is removed from input 1, the timer is reset and shuts down output 2. Thank you for any and all help
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Post by Gary Lecomte on Sept 5, 2014 7:33:29 GMT -8
If you are ONLY Driving Relays that Draw 85 mA. Why are you using the TIP122 Transistors? The 556 will drive those Relays Directly.
As to your Input 1 and Input 2, What are they Connected to? Input, Square Wave? Input connected to a High or Low source? Input from WHAT?
The Way your Circuit is drawn, makes no sense to me.
Seeing as your in CANADA, If you want to discuss this, I can Phone you. Just email me your Number. chemelec@hotmail.com
Gary
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91xr7
Junior Member
Posts: 51
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Post by 91xr7 on Sept 5, 2014 9:39:16 GMT -8
If you are ONLY Driving Relays that Draw 85 mA. Why are you using the TIP122 Transistors? The 556 will drive those Relays Directly. As to your Input 1 and Input 2, What are they Connected to? Input, Square Wave? Input connected to a High or Low source? Input from WHAT? The Way your Circuit is drawn, makes no sense to me. Gary okay, lets see here. First honestly i have little to no clue as to what i'm doing so i'm just following diagrams i have found online. As we know isn't the best choice, but can work thou. Okay i'll look up the Relay specs again, since i initially looked up the PN online and got 85ma, but i found out that's wrong? Going by Hella Catalogs, the Coil Resistance is 85ohms +/- 10%. So why use the TIP122? the schematic i used just called for them and they seemed to work in all honestly. And I can use the Transistor as a Switch between Input 2 and Output 2, Unless i can use the Input 2 to trigger the delayed on timer? Inputs are connected to Low by a ECU to Drive (turn on) the relays. So they are either Low (grounded) or High (Open?) maybe to help understand the delayed off circuit is just a copy of this circuit i found on F-Alpha.netthe Delayed on circuit would be from Clarkson_UK.com
But i tried to combine them to a single 556 IC. and yah the diagram/schematic isn't exact correct, i tried to use the 555 setup for drawing it, but just doubled it to separate the two circuits? i could try and redo it to be a single 556 like shown here?Sorry for the confusion, electronics even thou i'm interested in it and find it interesting, its not my strong suit saddly. thank you again thou PS two weekend ago i drove through Hedley, but the wife didn't want to stop
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91xr7
Junior Member
Posts: 51
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Post by 91xr7 on Sept 5, 2014 9:46:03 GMT -8
once again excuse my ignorance on this topic Since on a 555 pin 4 when pulled to Low will reset/stop the timing circuit from what i read. and usually pulling it high will allow it to commence. Now my theory (and we now know how bad that is) is to use a PNP transistor inline with Pin #4 with a Resister pull the pin to Low and having the Base of the transistor going to Input #1 allowing Pin #4 to go High in turn allowing the timing cycle to start. rough idea like this; Thank you once again. Kevin
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Post by Gary Lecomte on Sept 5, 2014 10:25:37 GMT -8
Send me your Phone Number. It is a FREE Call for me.
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91xr7
Junior Member
Posts: 51
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Post by 91xr7 on Sept 5, 2014 14:02:31 GMT -8
Heh oddly I'm not really a phone type person Also I'm more a visual / hands on type person when it comes to doing things. But if you think there is no other way then we can do a phone call then. Thank you, Kevin
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Post by Gary Lecomte on Sept 5, 2014 14:57:07 GMT -8
I Need to Confirm a Few Things. In you First write-up, You Said: Input 1 is "low" Input 2 is "high" On the Bottom of the Schematic it says: Input 1 is "Negative" Input 2 is "Negative" To Me, this means they are Both Low ? Obviously I Can't give a Schematic over the Phone, But it can help me better to understand what you need. As to a 555, it can Source or Sink up to 200 mA. If that relay is 85 Ohm, it draws 141 mA. And in a Vehicle with the battery charging at 14.5 volt it is 170 mA. That is Kinda High for a Relay. I have Many good relays here that Draw Less than 100 mA, even at 14.5 volts.
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91xr7
Junior Member
Posts: 51
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Post by 91xr7 on Sept 5, 2014 16:02:13 GMT -8
Yah sorry about that, I'm coming from the automotive electric side of things, so to me I think Negative and Positive when it comes to DC electrical . The ECU has two outputs that are pulled to Low when activated; 1. Fan Relay #1 ( Circuit; Input #1) 2. Fan Relay #2 ( Circuit; Input #2) The Circuit in Question has those two inputs and also three outputs as; 1. Fan Output #1 (Tied directly to Input #1) 2. Fan Output #2 (To be Delayed turning on with Input #2 as Ground source for Fan Output #2) 3. Coolant Pump (Labeled Output #3, Controlled by Input #1 and is delayed off when Input #1 is Pulled High The problem with the circuit above is that I need to reset the delayed on circuit whenever input 1 and/or input 2 are pulled high (Via the Relays). It works great on initial start up, But i can't use can't use Input #1 low signal to turn on the 556 since when that low signal is removed i loose the delayed off circuit too Also the relays being used are just standard Hella automotive relays, pn: 87499 , going by what your saying maybe a transistor is a good idea? Hopefully this explains thing a bit better?? And if there is a style of schematic you like please post a link or icture of? and I'll try to recreate mine to be like it? Thank you again, Kevin
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Post by Gary Lecomte on Sept 5, 2014 20:03:05 GMT -8
What I can tell you now: is if you put a 1K resistor between the Supply and the Cap going to Pin 6 in the First Schematic. Than if you supply a LOW pulse to the Junction of this resistor and cap, it will RESET the Delay Section to start over again.
Unfortunately with my Holiday coming up and having Company at this time, I don't have much free time for this.
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91xr7
Junior Member
Posts: 51
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Post by 91xr7 on Sept 5, 2014 21:12:10 GMT -8
What I can tell you now: is if you put a 1K resistor between the Supply and the Cap going to Pin 6 in the First Schematic. Than if you supply a LOW pulse to the Junction of this resistor and cap, it will RESET the Delay Section to start over again. Unfortunately with my Holiday coming up and having Company at this time, I don't have much free time for this. Hello I think i understand what you are getting at, Just got to figure out how to do a single low pulse to that point. Google i'll go! I really do appreciate you putting up with me and trying to help me on this, And everytime i try to do projects like this i get upset that the Highschool i went to canceled the Electronics coarse just as i was entering that school! Maybe i would of went the way of electronics and not Automotive (both where strong interests for me in my younger days) Thank you againPS i'm Jealous of anyone that's going to Australia, I've been bugging my wife for the past 6 years to go there! and it'll be mildly cheap (other then airfare) for us too since i have 8 Uncles that NSW and Victoria, with many a Cousin. Have fun down there.
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Post by Gary Lecomte on Sept 6, 2014 5:49:57 GMT -8
Hi Kevin, Here is how to Reset the Delayed ON, to REPEAT another delayed ON Output. Doing a Single Low Pulse is more difficult. But a Single LOW PULSE from WHAT Source? Could Possibly use a SCR. I would need a more detailed schematic of where you need this. Australia: My girl friend actually wanted to do the South Island of New Zealand, as well as Australia. But I thought that was bit too much. Just working out all the Air Fares and Main Hotels we need in Australia is a lot of searching to get descent Prices. Australia is EXPENSIVE. (In Ayers Rock, the hotels are around $300.00 Per Night.) Most other cities are LESS. Food in Australia is also expensive, compared to here. One Hotel in Carins, wants $17 per day, per person for Breakfast. (Just toast with Jam, Coffee or Tea, a Muffin and a Juice) I'll make my own coffee, thanks anyway. Attachments:
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91xr7
Junior Member
Posts: 51
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Post by 91xr7 on Sept 6, 2014 9:40:39 GMT -8
I have to look into the SCR thing later. I was just thinking of a transistor that switches "on" when the input/output #1 goes High via the power coming from the relay coil, and as input #1 goes low again the transistor turns off and the timing circuit starts up again?
I look more into this later today thou since this is the last weekend the in-laws are in town so we got some stuff to do before they head home overseas on Tuesday!
Also tell me about the expensive breakfast at hotels, we stayed at a place once that wanted a lot for basically nothing but went down the block to a place and was able to and be full for like half the price of the hotel!
Thanks again
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91xr7
Junior Member
Posts: 51
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Post by 91xr7 on Sept 7, 2014 10:25:32 GMT -8
Okay my latest idea based your attachment for this whole resetting issue. Excuse my very crude hand drawing, Least there isn't really that much to it. Sadly it uses a relay to give a short ground pulse. It is based on a Constant to Momentary Circuit , But i don't have a 1000uf Capacitor, just a 330uf. I do have 10K resistors, but wanted to try it with a 40.2K. For triggering i'm using a NPN transistor (2n3904 since i have a few) that the base is is connected to the output #2 via a 2.2K resistor When output #2 isn't pulled to low, the wire is high from the current (?) coming from the high side of the relay coil winding, in turn turning on the Transistor allowing flow from its emitter to collector. This allows Constant to Momentary circuit to "engage" causing a quick triggering on the relay. When output #2 is pulled low, the transistor turns off and in turn resetting the Constant to Momentary circuit in the link NOW i just need to figure out how to replace the Relay with say a transistor? I found a few circuits out there, but so far all that i have tried didn't work! I even tried this circuit, namely the left one since it was the one that seemed to work for me, but the issue it had was it turned on (triggered) the output on power up, which isn't much of a problem if both Inputs are high when that happens but if the inputs are low on power up. and i tried to modify it with the power on reset (?) circuits, but never got those to work either? Thank you again
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91xr7
Junior Member
Posts: 51
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Post by 91xr7 on Sept 7, 2014 10:35:58 GMT -8
NOW while laying in bed this morning, was thinking, this as we know this will be triggered by a ECU in a Car, NOW that same issue will be checking for the relays. NOW it just checks if there is a Open or Shorted (Ground and Positive)circuit. 1. Fan Relay #1 ( Circuit; Input #1) is wired directly to the relay so it should be good 2. Fan Relay #2 ( Circuit; Input #2) isn't wired directly to the relay, So my thinking is why not have input #2 turn on the delayed on circuit by having it tied into the 47K resistor instead of it going to ground (low), then have the TIP122 going to ground instead of Input#2. Then add a 85-100ohm resistor between Input #2 and Positive (high)? Would i need a diode to block the positive(high) going to the 47 resistor? Thank you Ps are you tired of me and my ramblings yet?
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Post by Gary Lecomte on Sept 8, 2014 6:23:29 GMT -8
Well I am NOT an Automotive Person. And Not Familiar with the ECU or what types of signals it supplies.
Actually I am still trying to figure out What Exactially is the Purpose of all this.
What are these two Fans and the Pump Doing?
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