Table 1.

Summary of the symbols employed in the proposed model. Comparison with similar studies is also presented.

Description	Symbol	Equivalent Symbol from Zhang et al. [22]	Equivalent Symbol from Wang et al. [23]	Equivalent Symbol from Kalantari et al. [9]
Resistance of the FSR *1	RFSR	R(σ) *2	Rr(σ) *2	Rtotal *2
Contact resistance	Rc	-	-	RCon
Bulk resistance *3	Rbulk	R(σ) *2	Rr(σ) *2	RPol
Voltage drop over RFSR	VFSR	U	U	U
Voltage drop over Rc	VRc	-	-	-
Voltage drop over Rbulk	Vbulk	-	-	-
Mechanical stress	σ	idem	idem	idem
Effective area at rest state *4	A0	- *5	- *6	- *5
Effective area for tunneling conduction	A(σ)	- *5	- *6	- *5
Power law for A(σ)	$A_1{\sigma }^{A_2}$	- *5	N(σ)/N(0) *6	- *5
Sensor physical area	AFSR	-	-	-
Contact resistance at rest state *4	$R_c^0$	-	-	- *7
Resistance of the conductive particles	Rpar	idem *8	idem *8	idem *8
Compressive modulus of the Polymer composite	M	idem	idem	idem
Height of the rectangular potential barrier	Va	idem	idem	idem
Width of the rectangular barrier at rest state *4	s0	idem	idem	idem

Hyphen symbol implies that such parameter is not embraced by the author. *¹ Also known as the total resistance; it comprises the series connection between R_c and R_bulk; *² Zhang et al. [22], Wang et al. [23] and Kalantari et al. [9] model the relative variation of resistance in regard to the experimentally measured resistance at rest state; see Equations (17), (23) and (24); *³ Also known as the tunneling resistance; *⁴ Rest state implies σ = 0; *⁵ The final formulations from Zhang et al. [22] and Kalantari et al. [9] assume the effective area for tunneling conduction as stress-independent , see Equations (17) and (24); *⁶ The quotient N(σ)/N(0) models the variation in the effective number of conductive paths with the applied stress, see Equation (23); *⁷ Although not explicitly stated by Kalantari et al. [9], the contact resistance is infinite at rest state as predicted by Equation (11); *⁸ All previous models embrace the contribution from the particles’ resistance, see Equation (12). However, they stated that R_par is negligible when compared to the tunneling resistance. Hence, they discarded it as in Equation (13).