The relay is OK. Just as already stated the transistor looses exactly 4V.
Here is the relay connected directly to 12V. The current is correct at 60mA and a coil restance of 200Ohm.
If your circuit is OK then the current should be 53mA (ULN2003 is equipped with darlington transistors)
The ULN2003A has a built in base resistor of 2K7. The ULN2001A has none. May be you should try that and use a lower resistance value at the base. On the other hand, why are you worried? 40mA instead of 60 for a G2R relay is good enough.
Also the switch is connected to VCC. If it has no explicit voltage label the voltage there is +5V which might be too low. Connect the switch to +12V and see what happens.
The relay is OK. Just as already stated the transistor looses exactly 4V.
Here is the relay connected directly to 12V. The current is correct at 60mA and a coil restance of 200Ohm.
If your circuit is OK then the current should be 53mA (ULN2003 is equipped with darlington transistors)
The ULN2003A has a built in base resistor of 2K7. The ULN2001A has none. May be you should try that and use a lower resistance value at the base. On the other hand, why are you worried? 40mA instead of 60 for a G2R relay is good enough.
I've tried with ULN2001A, and it ran correctly.I also put 16V insted of 12V (in schematic with ULN2803) as nominal coil voltage to compensate the voltage lost (4V) due to the resistor and the simulation ran corretly also.(see attached)
Boncuk said:
Also the switch is connected to VCC. If it has no explicit voltage label the voltage there is +5V which might be too low. Connect the switch to +12V and see what happens.
I did not understand well how you did find the Vce sat value, but I used to think that the ULN is able the give the exact current needed by the relay's coil.
here, I think the problem also come from the resistance of the ULN.
(see attached)