using a thyristor based diode circuit as shown in fig1 in these embodiments the transistors are formed as follows the collector 112 forms the emitter of transistor 810 the base of transistor 830 and the emitter of transistor 840 base diffusion 113 forms the base of transistors 810 and 820 and the emitter of transistor 830 base diffusion 114 forms the collector of transistor 830 and the base of transistors 840 and 850 the emitter 115 forms the collector of transistors 810 and 820 emitter 116 forms the emitter of transistor 820 and is connected via conductor 823 respectively 123 in fig1 to emitter 117 which forms the collector of transistor 850 emitter 118 forms the emitter of transistors 840 and 850 fig9 shows an esd circuit 900 according to another example embodiment of the present invention the circuit 900 includes transistors 910 920 930 and 940 connected between an input node 902 and ground 904 as shown with the base of transistor 910 connected to the collector of transistor 940 via conductor 923 the circuit 900 may be formed using a thyristor based diode circuit similar to the circuit 100 shown in fig1 with emitter 116 removed in such an embodiment the collector 112 forms the emitter of transistor 910 the base of.