Actually Yes, But since the current sources are not readily available, we use the voltage sources........ The rating 12v 5A means the switching is occured at 12V and it can carry 5A of current safely........
Actually it is ohms law, but instead of R (resistance) you have to use Impedance(z= R+jX where X is the inductive reactance) of the relay coil to calculate the current flows through it.
Oh. Okay, referring from your circuit version the voltage source connected to NO is 12v 5A. And the supplied amp will differ upon the device being controlled which is the coin box. Did I get that right?
Sometimes it will be there in the markings of relay indicating the coil resistance & X ( the reactance). if not you have to calculate it manually or refer the Data sheet for the relay (recommended).....How do I get the value X?
That is fly back diode ( freewheeling diode ) . if you prevent to use that diode in parallel with your relay , when your transistor is on , we don't have any problem . but when the transistor , wants to be turn off , according to the lenz law (E=L*di/dt) , the inductor of the relay , try to increase the voltage , up to hundreds of volt( at the reverse polarity) . thus that diode can does short circuiting that inductor opposition.and thus can keep your transistor.
Best Wishes
Goldsmith
kak111, yes you are right and I have no doubts on the using of the Transient Suppressors and I am myself an electronics circuit designer and do use it frequently.Diode suppression of EMF Generated HV Spike
Transient-voltage-suppression diode
Why do they use diodes 4148 in this circuit
Raza giving some false information?
No I am not giving wrong information. Please read and follow carefully what I said.
Yes..........And the supplied amp will differ upon the device being controlled which is the coin box...... that is right
But 5A is very large current. So you usually don't require that much current.The 5A providing battery is also costly...... as I said earlier if you want you can go for lower current rating...
Sometimes it will be there in the markings of relay indicating the coil resistance & X ( the reactance). if not you have to calculate it manually or refer the Data sheet for the relay (recommended).....
If you want to calculate manually, you have to place the multimeter accross the coil ends in resistance measuring mode... you will get Resistance........
in a similar way use an inductance meter to know the inductance (L) of the relay..... X =wL , where w =angular frequency)..........
All the best from RJK
You just jumped into conclusions about the function of D2. But nothing has been said or asked about it before. You didn't consider that it may be an intentional load, as it finally turned out.No I am not giving wrong information. Please read and follow carefully what I said.
You just jumped into conclusions about the function of D2. But nothing has been said or asked about it before. You didn't consider that it may be an intentional load, as it finally turned out.
Which I clarified.Raza giving some false information?
View attachment 67350
Hi Goldsmith,
Look at the attached circuit above. Yes D1 is a Freewheeling Diode and not the D2. I am asking about D2 not D1. D2 has nothing to do with any transient as per the circuit. D1 is in parallel to the relay coil and saves the transistor against any transient (High Voltage) produced by the relay coil while breaking circuit. D2 has no action in the transistor circuit. If you look at the circuit in the post# 14, I have put a RED BOUNDARY on the diode.
Dear Raza
Hi
Sorry , i thought that you talked about D1 . but about D2 , you're right.
Respect
Goldsmith
The coil not do not carry 5 amperes (may take a few mA) but the contact's current carrying capacity is 5 amperes in this case.12V, 5A is just a rating of relay. As Goldsmith told, Relay need 12V to activate the contacts and it's coil can carry current of 5A (maximum).
The coil not do not carry 5 amperes (may take a few mA) but the contact's current carrying capacity is 5 amperes in this case.
Goldsmith,Where is your post ? the post 14 isn't for you . it is for RAZA .
I saw that at some of the threads you did the behavior like this , can you tell us the reason ?
Are the relays used for :
1) Interfacing low voltage circuit to low voltage circuit
2) Interfacing low voltage circuit to high voltage circuit
3) Interfacing low current circuit to high voltage circuit
4) Interfacing low current circuit to low voltage circuit
5) Interfacing low current circuit to low current circuit
6) Interfacing low current circuit to high current circuit
7) Interfacing high current circuit to low voltage circuit
8) Interfacing high current circuit to high voltage circuit
9) Interfacing high current circuit to low current circuit
10) Interfacing high current circuit to high current circuit
11) Interfacing low voltage circuit to low current circuit
12) Interfacing low voltage circuit to high current circuit
13) Interfacing high voltage circuit to low voltage circuit
14) Interfacing high voltage circuit to high voltage circuit
15) Interfacing high voltage circuit to low current circuit
16) Interfacing high voltage circuit to high current circuit
???
Dear poxkix
Hi
Your question is simple and has a simple answer , but i can't understand , why , this huge values of replies , and long discussion occurs ?!!!
Relays are just simple devices , that if you give a voltage across it coil , it's contact will change the situation , simply ( on or off ) .
And you can use them simply .
Good luck
Goldsmith
All options (1...16) are possible and are used in different connections and circuits with relays and contactors.
In general, the relay should be understood as a component , where the control circuit generates only a magnetic field in a coil.
This magnetic field is used to generate force that close or open the switch contacts.
Magnetic field is generated by electric current or voltage (V = 3V .... 400V ac or dc) (I = 1mA .... 1000A ac or dc)
in case high current controlled relay voltage can be very low. (Needed power for switch action is UxI)
Contacts can act as switches for voltages and currents. ( V = 1 mV... 2kV ac and dc) ( I = 1mA... 25A ac and dc) ( or in contactors several kiloamperes )
whenever any of the relays are triggered the whole circuit goes kaput. I really don't know why.
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