50 watt Power Amp OTL by LM3900, 2N3055

This be power amp OTL 50Watt use IC LM3900 and 2N3055 x 3pcs transistors to pillar equipment. Follow very circuit keeps to are Class ab then have a voice good loud. When , be amp OTL you then are certain that build easy use power supply the group is one 70V sizes by must use Current low 2Amp go up. Then have a voice good another thing you will like that amplifier. This durability do not make a loudspeaker a lose easy.

LM3914          IRF3205           PT4115          2N2222A            NRF24L01

Driving stepper motor using ULN2003

The simplest way to drive stepper motor having lower current rating is using ULN2003. The ULN2003 contains seven darlington transistors. The ULN2003 can pass upto 500mA per channel and has an internal voltage drop of about 1V when on. It also contains internal clamp diodes to dissipate voltage spikes when driving inductive loads. The circuit for driving stepper motor using ULN2003 is shown below.

For higher current torque motors, you can use TIP120. The advantage is that the TIP120 can pass more current along with heat sink. The disadvantages are that the more wiring is required and four TIP120 is used to control the motor.