Central display field for information transmission system - has transistor controlled by electronic circuit in series with transistor controlled by evaluating transistor

摘要

The central display field, for an information transmission system, has an electronic control with two transistors in series controlling the display lamp. One transistor is controlled by the electronic control and the other is controlled by an evaluating transistor. A limiting resistor is connected in parallel with the base-emitter path of the second lamp transistor. - The control output is connected to a voltage divider with two outputs. The voltage at the second output is attained when the alarm contacts for the transmission system are both closed, to drive the evaluating transistor into conduction, thus causing the second lamp transistor to conduct.