Dual limit comparator (window comparator) made with LM339

The circuit in Figure 7 consists of two LM339s forming a window comparator. When the compared signal voltage Uin is between the threshold voltages (UR1<Uin<UR2), the output is high (UO=UOH). When Uin is not within the threshold potential range, (Uin>UR2 or Uin<UR1), the output is low (UO=UOL), and the window voltage ΔU=UR2-UR1. It can be used to determine whether the input signal potential is between the specified threshold potentials.