mariomoskis
New Member
hello,i am trying to control a dc motor (1.5-3) with a transistor 2n2222a, at the CI NE555 output i have (supply voltage-1)=7-1=6V,so with duty cycle=50% i have the 3V(3/6=50%) and with duty cycle=25% i have 1.5V(1.5/6=25%) on my motor. and the circuit is the next:
View attachment 62374
my transistor has gain=40 and the maximum load of y motor will be 0.3A,so i need at my base a current at least I=0.3/40=7.5mA to get saturation, and the resistir at the base must be 6/7.5=800 maximum to get this, so i use a resistor=270ohm
-all which i said is correct?
-and the problem is that when i make the circuit, the transistor get so hot, why am i having this problem? how could i solve this problem?
pd: the diode on parallel with my motor is in correct way!
-and another question, the Vcc is 7V as i said so when the transistor is on cut-off which voltage read my motor? because if it is 7V i will burn it.
could somebody help me with this, i am really loss alot time with this but i don´t get a solution
thanks
View attachment 62374
my transistor has gain=40 and the maximum load of y motor will be 0.3A,so i need at my base a current at least I=0.3/40=7.5mA to get saturation, and the resistir at the base must be 6/7.5=800 maximum to get this, so i use a resistor=270ohm
-all which i said is correct?
-and the problem is that when i make the circuit, the transistor get so hot, why am i having this problem? how could i solve this problem?
pd: the diode on parallel with my motor is in correct way!
-and another question, the Vcc is 7V as i said so when the transistor is on cut-off which voltage read my motor? because if it is 7V i will burn it.
could somebody help me with this, i am really loss alot time with this but i don´t get a solution
thanks