Hi all
I am trying to build an H-bridge using TIP 122 npn Darlington pair transistors and TIP 127 pnp's.
The bridge got the 3V motor to turn one way but refused to reverse. The bases had 350 ohm resistors and I did not include 4 diodes since the data sheet shows that TIP's have their own protective diodes. My power source is a 6V battery pack.
When it would not reverse, I tried each transistor separately with only the motor as load across the emitter/collector. The base was biased with a 2k to infinite ohm CdS photoresistor. The transistors turned the motor on individually but got hot in about 30 seconds of use. Is this normal? Surely if one is driving something as small as a 3V DC motor, the TIP should not overheat so?
I copied the circuit found half way down the page at http://multyremotes.com/dc-motor-controller.htm
Any suggestions on these two problems would be most welcomed.
I am trying to build an H-bridge using TIP 122 npn Darlington pair transistors and TIP 127 pnp's.
The bridge got the 3V motor to turn one way but refused to reverse. The bases had 350 ohm resistors and I did not include 4 diodes since the data sheet shows that TIP's have their own protective diodes. My power source is a 6V battery pack.
When it would not reverse, I tried each transistor separately with only the motor as load across the emitter/collector. The base was biased with a 2k to infinite ohm CdS photoresistor. The transistors turned the motor on individually but got hot in about 30 seconds of use. Is this normal? Surely if one is driving something as small as a 3V DC motor, the TIP should not overheat so?
I copied the circuit found half way down the page at http://multyremotes.com/dc-motor-controller.htm
Any suggestions on these two problems would be most welcomed.