Again, as with the NPN unit you may also use 3 diodes instead of
2 in series, and use a 6.8ohm resistor. Those with very sharp eyes may
notice that the photo (Fig. 7) is actually of a limiter made with a PNP
transistor, 6.8 ohm resistor, and 3 diodes as shown in this schematic.
Fig. 8d PNP three diode Muscle Wire current limiter circuit.