Question about 555 timers

[Moneer81]

hey guys:

I am new to electronics and this problem is getting me very confused, your help will be appreciated.

It is a design problem with a 555 timer. When you push button PB 1, a 6V dc motor starts running, and pushing PB 2 causes the motor to stop.

The question that I don't even know its meaning is: "Justify that a negative pulse to ground is input to the particular 555 input when a push button is pressed. (The trigger and reset inputs have high resistance.) Which push-button type should be used, NO or NC? And what curren limitation is placed on the motor?"

any clue on what to do here? Thanks.

 

[Phasor]

In this mode, the 555 is simply working as a logic gate, with the logical equation:

M = (NOT T) AND R

M = motor
T = threshold pin
R = reset pin

ie, the motor will run when the threshold is taken low (switch closed) AND the reset is high (switch open). Under any other condition, the motor will not run.

The current limitation of the motor, is limited by the available output current of the 555. Refer to the datasheet for this figure.