Forward and reverse control circuit of micro DC motor b

Forward and reverse control circuit of micro DC motor b

Shown is the forward and reverse control circuit of a micro DC motor . (a) Shown is the mechanical control forward and reverse control circuit.
When the forward switch is turned on, VT1 and VT3 are turned on, and the positive pole of the 12V power supply is added to the motor through VT3 ( p terminal, the current flows from (D to ⑧, and the motor rotates in
the forward direction.
    When the reverse switch is turned on, the VT2 and VT4 transistors are turned on, and the current flows from (p to (D, connected to the negative pole of the 12 V power supply via VT4, and the motor rotates in the reverse
direction.
    Figure (b) shows an electronic forward and reverse control circuit. The control circuit of the motor is composed of a bridge drive circuit. When
there is a high-level control signal at the forward control end, the composite transistor is turned on to make VT2 in the bridge transistor The base is connected to the base of VT4, so VI2 and
VT4 are connected. The positive output current of the 12 V power supply is added to the (p terminal) of the motor through VT2. The current comes out from the ⑤ terminal after passing through the motor winding, and
goes to the power supply through VT4. Negative pole (ground), so the motor rotates forward.
    When a high level is applied to the reverse control terminal, the reverse control composite transistor is turned on, causing VT1 and VT3 in the bridge transistor to be turned on, and the current
flows from the @ terminal of the motor to ④, Make the motor rotate in reverse direction.