Saturday, September 20, 2014

bidirectional transistor motor driver for robotic project/ H bridge motor driver

this is the very useful motor driver circuit and its easy to make. this circuit is used in robotic project to move the robotic wheel front back right and left. this circuit is composed of two npn and two pnp transistors and some resistor. you need to have two switch to change the direction of the motor. here the transistors are acting on the its switching application. when both switches are off then motor donot move. when one of the switch is on then the npn of the one and the pnp of another side will be on so current flow through motor. so motor is on. when upper pnp is on on the left side, its lower npn is of and right side lower npn will be on but right side upper pnp will be off when switch is pressed at right side. note switch on means logic 0 and switch off means logic 1 if you are facing problems you can comment here. for the full description i ll upload the working video on youtube.com. check my channel sangit.niroula. this circuit is simulated in proteus simulator.

Monday, September 1, 2014

automatic street light using two transistor

automatic street is a very interesting circuit and using it we can make the light lamp on at night time and off at day time. this circuit is very simple to understand and make. components required -> two bc547 transistors --> resistors of value 2.2kohm and 330ohm both two --> light dependent resistors ->>>light emitting diode -->> 9v battery circuit diagram in night time, the value of light dependent resistor is very high and it makes the first transistor off so the second transistor will get base current and and it will be on so the led glows at this time. in day time, the resistance value of light dependent resistor is very low so it makes the first transistor on and the current flows through the first transistor therefore the second transistor will not get the base current so it will be off.. therefore at day time light will be off. still you have any confusion making this circuit on breadboard and matrix board, you can comment here/.......... thanks