audio guru i just biult it from a circuit off the net i dont know the supply voltage to the timer when i press the button but the relay i used is 12 volts rated and i even used 12 volts input to the circuit from a 12 volts lead acid cell battery , as for the 0.1uf ceramic and 10uf electro from supply to ground you recamended if ive got it correct, ill try that to but should i put them parralell the ceramic and elctro, to each other or sierieshigh voltage photo flash capacitor charger
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audio guru i just biult it from a circuit off the net i dont know the supply voltage to the timer when i press the button but the relay i used is 12 volts rated and i even used 12 volts input to the circuit from a 12 volts lead acid cell battery , as for the 0.1uf ceramic and 10uf electro from supply to ground you recamended if ive got it correct, ill try that to but should i put them parralell the ceramic and elctro, to each other or sieries
audioguru2
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Hi Steven,
You must measure the supply voltage to your timer circuit. If the battery voltage is low, it won't be able to supply the 400mA current spike from the 555's switching.
The supply bypass caps are each connected from the 555's supply pin to ground (in parallel). The ceramic cap is for very high frequencies and the electrolytic for lower frequencies and to supply local current that can't travel quickly through the inductance of the long wires from the battery.
What is the resistance of your relay coil? Maybe it is so low that the resulting high current is too much for the tiny series 1N4148 diode.
You must measure the supply voltage to your timer circuit. If the battery voltage is low, it won't be able to supply the 400mA current spike from the 555's switching.
The supply bypass caps are each connected from the 555's supply pin to ground (in parallel). The ceramic cap is for very high frequencies and the electrolytic for lower frequencies and to supply local current that can't travel quickly through the inductance of the long wires from the battery.
What is the resistance of your relay coil? Maybe it is so low that the resulting high current is too much for the tiny series 1N4148 diode.
ive got a 10uf electro already in that circuit ,so do i still add the electro and ceramic in parralell from supply to ground still and i forgot to mention i have a 1n4004 diode across the relay inputs for protection is that nessisary when i got the 2 x 1n4148 diodes , and should i replace the diodes for the same as on the relay , ive written down your recamendations and ill apply these as soon as possible as im flat out at the moment, and the 12 volts lead acid cell battery i used has a full charge to
audioguru2
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Hi Steven,
The 10uF electro in your 555 circuit is the timing cap that has nothing to do with the need for supply bypassing with the 2 additional caps.
I don't know where you connected a 1N4004 since relays don't have inputs. Across the contacts?
I can't remember the circuit of your HV driver so I don't know if a protection diode across the relay contacts will do any good, but it certainly won't do any harm.
I don't know if you should replace the 1N4148 diodes because you don't tell me the resistance of your relay coil. Sure, replace them anyway with 1N400x diodes.
You also don't tell me how much voltage the 555 circuit is putting across the relay coil.
The 10uF electro in your 555 circuit is the timing cap that has nothing to do with the need for supply bypassing with the 2 additional caps.
I don't know where you connected a 1N4004 since relays don't have inputs. Across the contacts?
I can't remember the circuit of your HV driver so I don't know if a protection diode across the relay contacts will do any good, but it certainly won't do any harm.
I don't know if you should replace the 1N4148 diodes because you don't tell me the resistance of your relay coil. Sure, replace them anyway with 1N400x diodes.
You also don't tell me how much voltage the 555 circuit is putting across the relay coil.
audio guru i apologise for the lack of information i was in a war with my partner yesterday and some other times and ive been so distracted that i just let my electronics idle for a few days till i know that i was gona get some uninterupted peace , hang in there audio guru ill get to these
audio guru i was lucky to be able to get these details as follows without inturuption, the relay coil resistance is 40.4 ohms, the supply voltage to the timer with the test battery was 9.83 volts but its the same as the battery voltage and i dident realize it was low in voltage , now the actual battery i first used to power the relay timer is 12.58 volts and thats the same battery in my high voltage photo flash capacitor charger , so what ever battery i use i was still getting the same small problem , oh i have to go pick up a carton of soft drinks for the women. say you dont have any remote controll to turn the chatterbox partner off do you ha ha ha ha its slowing my progress down in electronics
audioguru2
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Hi Steven,
My wifey used to nag me, "Are you making another one?", "Your LEDs are blinding me" and "Get off the internet". But now that she has taken up knitting and going to cooking school, she doesn't bother me very much!
Ah, now we get to know most of the details of your circuit, except the most important one: What is the voltage across the non-functioning relay coil? But now we can calculate it from the relay coil's resistance and the 555's and 1N4148's spec's.
1) Your battery was dead. I suspected it but even a good battery doesn't help.
2) The 40 ohm relay coil is like a dead short to a little 555 and a little 1N4148. The resistance of the coils in the 12V relays that I use measure 1K and 2.2K ohms.
3) The 555 is rated for up to 200mA of output current. With 200mA, its output typically has a 2.5V loss. Your 40 ohm relay will draw 300mA from 12V. Therefore the 555 will probably have a 3V loss or more. A 3V loss at 300mA results in 900mW of dissipation, which is very close to the 555's maximum temperature rating. It might melt.
4) The 1N4148 is rated for up to 100mA continuous current. With the relay's 300mA it will typically have a voltage drop of 1.1V or more, and might also melt.
So the circuit's voltage loss is 3V or more for the 555 and 1.1V or more for the 1N4148. If you subtract those losses from your 12.58V battery, you end up with only 8.48V or less across the relay coil.
A 12V relay is guaranteed to work with 9V or more.
That's why your circuit doesn't work. Ohm's Law, a couple of measurements and the datasheets explain it all.
When you use a relay with such a low coil resistance, you're going to need a power transistor to drive it.
My wifey used to nag me, "Are you making another one?", "Your LEDs are blinding me" and "Get off the internet". But now that she has taken up knitting and going to cooking school, she doesn't bother me very much!
Ah, now we get to know most of the details of your circuit, except the most important one: What is the voltage across the non-functioning relay coil? But now we can calculate it from the relay coil's resistance and the 555's and 1N4148's spec's.
1) Your battery was dead. I suspected it but even a good battery doesn't help.
2) The 40 ohm relay coil is like a dead short to a little 555 and a little 1N4148. The resistance of the coils in the 12V relays that I use measure 1K and 2.2K ohms.
3) The 555 is rated for up to 200mA of output current. With 200mA, its output typically has a 2.5V loss. Your 40 ohm relay will draw 300mA from 12V. Therefore the 555 will probably have a 3V loss or more. A 3V loss at 300mA results in 900mW of dissipation, which is very close to the 555's maximum temperature rating. It might melt.
4) The 1N4148 is rated for up to 100mA continuous current. With the relay's 300mA it will typically have a voltage drop of 1.1V or more, and might also melt.
So the circuit's voltage loss is 3V or more for the 555 and 1.1V or more for the 1N4148. If you subtract those losses from your 12.58V battery, you end up with only 8.48V or less across the relay coil.
A 12V relay is guaranteed to work with 9V or more.
That's why your circuit doesn't work. Ohm's Law, a couple of measurements and the datasheets explain it all.
When you use a relay with such a low coil resistance, you're going to need a power transistor to drive it.
audio guru your a genious anyhow i couldent figure out at first why the relay still worked and the open contacts close ok untill i ran one wire to it the postiive to be closed to switch on the driver circuit when the other negative input ran directly to the neg in of driver circuit , the timer never gets hot nor dose the relay and if i use it away from the circuit like use another battery it works fine and if i rig up another circuit and ran the postive to be closed to the relay open contacts and then to another 12 volts battery and from there to something else it works good at switching it on but when i used it to switch the flyback driver circuit in the hv cap charger on for ten seconds the relay then wont work . ive yet got to put in those 2 capacitors you recamended to see if it makes some difference , as soon as the effects of the war between me and my fiauncee wears off and i know im gona get some uninterupted time to get to this
audioguru2
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Hi Steven,
A voltage measurement across your relay coil will tell you what is happening with your circuit, but not what is happening with your lady.
A voltage measurement across your relay coil will tell you what is happening with your circuit, but not what is happening with your lady.
audioguru2
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Steven, the point of this discussion is that the relay's voltage is too low when driven by a 555 and 1N4148 that are straining so hard to cope with such a high current that they reduce the voltage to the relay. Your 12V relay's coil is probably getting less than 8.5V. Measure it to see. Maybe you were measuring the voltage at the relay's contacts by mistake.
audio guru i disconected the 2 input wires to the relay and get the same votage as the battery supply when i measured it , is there something not right here i measured the only input to the regulater correctly and i dident have the relay contacts hooked up when i did it , the relay still works fine no heating what so everaudio guru ive added a few more wires to the relay coil and tried another test this time useing the relay to switch on an led via the resister and when i push the button the relay switches on the led for the set time then turns off like its suposed to go and i remeasured the voltage and found it to be exactly the same as the battery voltage , of course i used the battery with a measured voltage of 12.58 volts and its the voltage i measured to the inpuit of the relay coil , as for the relay contacts i did3ent have then wired up this time but i ended up useing one on the relay inputs bridged to one of the contacts so to mshare then the second wire i used was the 12 volts input to the positive of the circuit from the fully chgarged battery and i hadd the resisters in pplace for the led and it worked fine so ill run another test by linking it to the driver circuit if it goes this time then the fault may be in my wireing to the relay contacts, oh yeh i got to add those 2 capacitors as recamended by you so hang in there audio guru, ill get to it, i apologise if i cant anserw many of your qestions as im not much of a technicle exsplanation type , and you know more than i do and im still lerning as i go ,and with electronics you never stop lerning as there is to much to not lern and it will take along time to lern it all , but some of the helpfull diagnostic stuff you post in trying to help solve some of the problems that some may have in electronics circuit s is more helpfull than you realize and this inspiration is is important , i read your posts with envy and are amazed at how you master the art of diagnoseing a circuit just by looking at itwwith a bit of improviseing and some more exsperiments heres some capacitors i may be able to charge up with the same circuit
View attachment 37254
View attachment 37254
Hi Steven,
Do you collect capacitors? ;D
You can charge those caps (first pic) directly from mains via a rectifier bridge to about 340VDC. Your mains power is 240AC, right? Maybe you should use a resistor is series not to pop your circuit breakers or fuses! Be careful, these caps can kill you if you mess with them.
Do you collect capacitors? ;D
You can charge those caps (first pic) directly from mains via a rectifier bridge to about 340VDC. Your mains power is 240AC, right? Maybe you should use a resistor is series not to pop your circuit breakers or fuses! Be careful, these caps can kill you if you mess with them.
audioguru2
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Yeah sure!
Charge those 50 capacitors to 340V and put them all in series.
Wow! The resulting 17,500V at a high discharge current is bound to do some nasty damage. ;D
Charge those 50 capacitors to 340V and put them all in series.
Wow! The resulting 17,500V at a high discharge current is bound to do some nasty damage. ;D
great to hear from you ante im well aware of the dangers of the larger electro capcitors especially those large photo flash capacitors , i can emagine the size of the camera they came from ha ha ha just kidding,most of my capacitors used to be in my upstairs cubboard when it used to get hot so i hope they still work ok i was told they could be zapped back to life, and that when your breaking them in to charge them at a lower voltage than there voltage rateing and slowly work it up, anyhow its a ruch here as i work on other ideas so the caps will wait ,
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