Miniature Open & Encapsulated AF Transformer Miniature PCB mounting audio frequency transformers suitable for isolating and impedance matching applications.,The open types are mounted by means of a clamp with spade feet which may be bent over when securing to a PCB. The enclosed type is fully encapsulated in a glass filled nylon case. Z1606 is encapsulated. Manufacturer Part No. Z1606 E187A E187B Z1604 Type Encapsulated Open Open Encapsulated Turns ratio 1:1 C.T. 1:1 C.T. 3·6:1+1 1:1 C.T. Primary Impedance 800Ω 800Ω 3kΩ 600Ω Secondary Impedance 800Ω C.T. 800Ω 250Ω + 250Ω 600Ω