Relay curcuit

[sniper007]

Hi

I want to realize one curcuit with relay switch. Please tell me is this curcuit correct ?

**broken link removed**

Maybe missing emitor resistor or something else ?

sniper

 

[ecerfoglio]

Hi

I want to realize one curcuit with relay switch. Please tell me is this curcuit correct ?

Should be OK. Perhaps the base resistor is a little low at 100 Ω, 1K seems better (Ibase = (supply - drops) / R = (5V - 2 V) / 1K = 3 mA; verify if your transistor will saturate with that currrent at the base)

Maybe missing emitor resistor or something else ?
sniper

No, it does't need one.

 

[sniper007]

(Ibase = (supply - drops) / R = (5V - 2 V) / 1K = 3 mA

Why 2V ?

I intend to use 8V input and 2n2222.

Ib=(8-0.6)/1k = 7.4mA

Should be ok?

 

[Willbe]

What's the coil resistance?
The diode should be a switching type and should be able to handle the coil current momentarily.
How much current/voltage can the I/O pin source at what voltage/current?

 

[ecerfoglio]

Why 2V ?

I intend to use 8V input and 2n2222.

Ib=(8-0.6)/1k = 7.4mA

Should be ok?

2 V (aprox) accounts for de drop across the transistor (B-E) and the µcontroler (Vsupply - VoH), about 1 V each

The 5 V is the µcontroler's supply. I assumed that you were using that voltage.

The relay's supply should match the relay's coil voltage - It may be 5V, 8V, 12v or wathever you have at hand.

 

[sniper007]

So, here is my actually schematic:

**broken link removed**

I don't have ucontroller but receiever for ramp. This receiver have output 8V while i press button on remote control. When i press button would like to relay activate.

The relay's supply voltage is 6V because i have 6V relay

will it work circuit?

I hope you understand my problem

 

[ecerfoglio]

Yes, there should be no problem.

The three "low voltage grounds" (receiver's ground, transistor's emiter and 6 V supply's negative) must be tied together.

 

[sniper007]

OK, thanks a lot!