D1 and Q2 what is the role of, why can't a 3 pin directly to Q5

CodePudding user response:

Actually,
555 output enough for 8050, completely don't need to increase the level of magnification,
Drawing people don't have enough understanding to the device,

CodePudding user response:

D1: dc motor have certain inductance characteristic, current closed will produce a voltage surge leading to breakdown, switch components and D1 can absorb it avoided voltage surge current,

CodePudding user response:

D1 for motor induced voltage discharge
Of two triode darlington is not just for the sake of magnification, sometimes is also a demand for voltage drop, from the circuit can push 555 3 pin output level through the diode also received another circuit, circuit didn't see so cannot further analysis, but from darlington connection shows about 0.7 * 2=1.4 V voltage,

CodePudding user response:

D1, the motor is inductive load, when stop running or motor reverse phase, may produce high peak voltage, the voltage can damage Q2Q5, can join D1 protection;
Q2, composition of Q5 darlington pipe, ensure driving ability;