Main technology - thermal resistance parameters:

Model	R25+-20% (Ω)	Steady state current (A)	Residual resistance (Ω)	Dissipated power (mW/℃)	time constant (S)	working temperature （℃）
3D-9	3	4	0.120	11	35	-55/+200
4D-9	4	3	0.190	11	35	-55/+200
5D-9	5	3	0.210	11	34	-55/+200
6D-9	6	2	0.315	11	34	-55/+200
8D-9	8	2	0.400	11	32	-55/+200
10D-9	10	2	0.458	11	32	-55/+200
12D-9	12	1	0.652	11	32	-55/+200
16D-9	16	1	0.802	11	31	-55/+200
20D-9	20	1	0.864	11	30	-55/+200
30D-9	30	1	1.022	11	30	-55/+200
50D-9	50	1	1.252	11	30	-55/+200
80D-9	80	0.8	2.010	11	30	-55/+200
2.5D-11	2.5	5	0.095	13	43	-55/+200
3D-11	3	5	0.100	13	43	-55/+200
4D-11	4	4	0.150	13	44	-55/+200
5D-11	5	4	0.156	13	45	-55/+200
6D-11	6	3	0.240	13	45	-55/+200
8D-11	8	3	0.255	13.5	47	-55/+200
10D-11	10	3	0.275	14	47	-55/+200
12D-11	12	2	0.426	14	48	-55/+200
16D-11	16	2	0.470	14	50	-55/+200
20D-11	20	2	0.512	15	52	-55/+200
30D-11	30	1.5	0.667	15	52	-55/+200
50D-11	50	1.5	1.201	15	51	-55/+200
80D-11	80	1.2	1.656	15	51	-55/+200
1.3D-13	1.3	7	0.062	13	60	-55/+200
1.5D-13	1.5	7	0.073	13	60	-55/+200
2.5D-13	2.5	6	0.088	13	60	-55/+200
3D-13	3	6	0.092	14	60	-55/+200
4D-13	4	5	0.120	15	67	-55/+200
5D-13	5	5	0.125	15	68	-55/+200
6D-13	6	4	0.170	15	65	-55/+200
7D-13	7	4	0.188	15	65	-55/+200
8D-13	8	4	0.194	15	60	-55/+200
10D-13	10	4	0.206	15	65	-55/+200
12D-13	12	3	0.316	16	65	-55/+200
15D-13	15	3	0.335	16	60	-55/+200
16D-13	16	3	0.338	16	60	-55/+200
20D-13	20	3	0.372	16	65	-55/+200
30D-13	30	2.5	0.517	16	65	-55/+200
1.3D-15	1.3	8	0.048	18	68	-55/+200
1.5D-15	1.5	8	0.052	19	69	-55/+200
2.5D-15	2.5	7	0.070	19	79	-55/+200
3D-15	3	7	0.075	18	76	-55/+200
4D-15	4	6	0.097	20	76	-55/+200
5D-15	5	6	0.112	20	76	-55/+200
6D-15	6	5	0.155	20	80	-55/+200
7D-15	7	5	0.173	20	80	-55/+200
8D-15	8	5	0.178	20	80	-55/+200
10D-15	10	5	0.180	20	75	-55/+200
12D-15	12	4	0.250	20	75	-55/+200
15D-15	15	4	0.268	21	85	-55/+200
16D-15	16	4	0.276	21	70	-55/+200
20D-15	20	4	0.288	17	86	-55/+200
30D-15	30	3.5	0.438	18	75	-55/+200
0.7D-20	0.7	12	0.018	25	89	-55/+200
1.3D-20	1.3	9	0.037	24	88	-55/+200
3D-20	3	8	0.055	24	88	-55/+200
5D-20	5	7	0.087	23	87	-55/+200
6D-20	6	6	0.113	25	103	-55/+200
8D-20	8	6	0.142	25	105	-55/+200
10D-20	10	6	0.162	24	102	-55/+200
12D-20	12	5	0.195	24	100	-55/+200
16D-20	16	5	0.212	25	100	-55/+200

NTC thermistor selection should consider the following points:
Maximum rated voltage and filter capacitance
The size of the filter capacitor determines the size of the NTC should be chosen. For a size of NTC thermistor, allowing access to the size of the filter capacitor is strictly required, this value is also related to the maximum rated voltage. In power applications, the power surge is due to capacitor charging, so it is usually used to assess the capacity of the NTC thermistor to withstand the surge current with the capacitance of the given voltage value. For a specific NTC thermistor, the maximum energy can bear has been identified, according to the resistance in first order circuit energy consumption formula of E=1/2 * CV2 can be seen, which allows access to the value of capacitance and rated voltage is proportional to the square of the. In simple terms, the greater the input voltage, the smaller the maximum capacitance value is allowed, and vice versa. The specification of the NTC thermistor product generally defines the maximum capacitance that allows access to the 220Vac. Assuming a certain application conditions the maximum rated voltage is 420Vac, the filter capacitor value is 200 F, according to the above formula can be converted into energy equivalent capacitance under the 220Vac value should be 200 * 4202/2202=729 ~ F, so we must choose the 220Vac to allow access to the capacitance value larger than 729 F in model selection.
The maximum starting current maximum allowed value of starting current products and long-term load in the NTC thermistor on the current electronic products allows the value of NTC is determined by the resistance of the thermistor. Assuming the rated power input is 220Vac, the resistance is 1 ohms, the maximum starting current allowed is 60A, then select the minimum NTC value in the initial state of the Rmin= (220 x 1.414/60) -1=4.2 (omega). At this point, to meet the conditions of the NTC thermistor will generally have one or more, at this time and then according to the following method to choose.