Voltage testing arrangement, has resistors together forming voltage divider for measuring input of microcontroller, and NPN transistor with base connected with output through divider, where control output of microcontroller is switched off

摘要

The arrangement has a microcontroller provided with a control output and a measuring input, where voltages (U3, U2) at the input and output lie within preset operating ranges. An NPN transistor (T1) has a collector connected to a switching point. An emitter is connected with a reference potential through a resistor (R3). The resistor together with another resistor (R4) form a voltage divider (R1, R2) for the measuring input. The control output of the microcontroller is switched off. A base of the NPN transistor is connected with the control output through the voltage divider.