Select your language

In an article on the design of broadband transformers (SHPT) on the ferrite rings for LW transistor power amplifiers, it is noted that the cross section of the ring should be 0.25 cm2 for every 100 watts. The coil inductance is calculated by the formula Lmin[MKrH]=4R/(27pf)where R is the resistance of the circuit which includes the winding [Ω], a f - the lower the operating frequency of SHPT [MHz]. Thus, for f=1.8 MHz and R=50 Ω Lmin=18 µh.


Fig.1

Fig.2

In Fig.1 and 2 for this example shows the schema of transformers 1:4 and 1:9 respectively. The first of these is wound four wires held together with condition obtain one coil inductance of 4.5 mH, and the windings are connected according to Fig.1. Second SHPT is wound simultaneously with six wires of one coil inductance 2 mH.

Author: Zoltan Szabo (HA9PN); Publication: N. Bolshakov, rf.atnn.ru