Simple op-amp question, basic use

Hi.

I have some lm741 opamps, and I've been trying to use them.
I created a +vcc -vcc supply using two 9v batteries with the gnd as the point in which one batt's + is connected to the other's - .

I tried to create the basic configurations: first - open loop, ie vee to the -9, vcc to +9, and the input to the gnd or +vcc (for trials...). I expected the output to yield 9v but nothing was outputted (I connect to the output a simple motor which runs on less than 9v, but it didn't spin). I expected the motor to run when the input is connected to +vcc and to stop when the input is connected to gnd. But - nothing happens at all...
I also tried a simple negative feedback with both inverting and non-inverting, using several resistors (to create some different gains). And nothing on the output.

When I tried to connect the voltage inputs (vee,vcc) the other way (ie +9 to vee, -9 to vcc) I just got the motor to work but the opamp got real hot real fast so I disconnected.

Is there something I'm missing? some other wire perhaps I should be connecting? It should be really simple... I tried it on some 3 opamps I got and on all I get the same result.

Thanks.

The setup is somewhat beyond basic OP use, I suppose.

In your first test, you have proven, that the motor won't run with the maximum output current provided my an LM741, typically 25 mA.

In your second test, you most likely fried the OP. The output is short circuit protected and should tolerate the mistreatment of your first test. But it's not prepared for supply voltage reversal.

It's the smallest motor (picture attached)... So which amp should I use to drive it? It works fine on 3v batteries and I was hoping that an opamp would drive it.

https://music.columbia.edu/~douglas/classes/motor_mania/DC_simple2.jpg

It's a cheap Johnson (or similar) motor showing some bearings/brush friction and respective initial current.

By adding a complementary transistor output stage, you can provide sufficient current for the motor.

741 can not sink or source the amount of current that a motor needs. u can use simple transistor switch, darlington pair or an IC "ULN2003" or "ULN2008" for using low resistance loads with opamps. refer to its datasheet for ckt connection. ULN2003 Datasheet pdf - SEVEN DARLINGTON ARRAYS - ST Microelectronics

Hi radagast,

I think you have to clarify some points:

I tried to create the basic configurations: first - open loop, ie vee to the -9, vcc to +9, and the input to the gnd or +vcc (for trials...).

Which input? Both?

I expected the output to yield 9v but nothing was outputted (I connect to the output a simple motor which runs on less than 9v, but it didn't spin).

What means "nothing was outputtet"? Vout=0 ? What is the purpose of the motor? Only a voltage sensor?

I also tried a simple negative feedback with both inverting and non-inverting, using several resistors (to create some different gains). And nothing on the output.

negative feedback with "both inverting and non-inverting" .....(gain or inputs?). Not clear!.

When I tried to connect the voltage inputs (vee,vcc) the other way (ie +9 to vee, -9 to vcc) I just got the motor to work but the opamp got real hot real fast so I disconnected.

Are you not sure about the correct supply connections?

Thanks everyone. I looked into the lm741 datasheet and I really see that the output current is too low.

I'd appreciate any recommendations for bjt transistors to create my complementary output stage. I don't really have requirements, just need a/several model names to know what to buy. I guess I need it to be driven by +9v and -9v and deliver about 50-100mA to the motor.

Thanks.