Digital tube extinguishing signal circuit diagram

In a multi-digit display, in order to emphasize certain numbers, an extinguishing signal is added to this circuit to make the digital tube light up or darken. The principle is to use Q1 and Q2 to reduce the cathode voltage of the digital tube from the normal value of 200V to 100V, making the digital tube dim. The control signal is input from the base of Q2. When the fire extinguishing signal is 0V, Q2 is cut off, and the cathode voltage of the digital tube is 200V. When the fire extinguishing signal is 2V, Q2 is turned on and the cathode voltage drops to 100V.

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