Bill Of Materials for "C/ESR Meter"

Board revision v1.0.7 (Jun 2024)

Resistors

Quantity	References (1% 1/4 watt 400mil)	Value	Comments
1	R1	1500R	AD620 gain "33" (default 10Ω range). Theoretical 1543.75Ω. If R1=1500R --> G=31.9
1	R2	75R	AD620 gain "330", (1Ω range). Depends on $R_{on}$ of CD4066B at 5v which should be measured. If R2=75R and (CD4066B $R_{on} @5v$)=92R --> G=337
1	R3	180R	Capacitor charge current limiter to 10mA. $I_o = \frac{V_{ref} - V_{be}}{ R_s } = \frac{2.5v - 0.7v}{ 180Ω } = \frac{1.8v}{ 180Ω } = 0.01A = 10mA$
2	R4, R24	560R	ADC and Z1 current limiters, any approximate value will work fine.
1	R5	270k	Together with R6 they form a voltage divider to measure the battery level. Their ratio must be defined in the source code: `#define VBATT_FACTOR 3.7 // = 1+(R5/R6) = 1+(270k/100k) = 1+(2.7) = 3.7`
7	R6, R16, R17, R18, R19, R20, R23	100k	R6 together with R5 form a voltage divider, see R5. The others are pull-up and pul-down resistors, any approximate value will work fine.
2	R7, R26	20k	They are part of the voltage dividers for voltage references.
1	R25	12k	It is part of the voltage dividers for voltage references.
7	R8, R9, R10, R12, R13, R14, R15	10k	R8 and R9 are part of the voltage dividers for voltage references. The others are pull-up and current limiters, any approximate value will work fine.
3	R11, R21, R22	100R	MOSFET current limiters, any approximate value will work fine.

Quantity	References	Value	Comments
2	C1, C2	4.7nF	Non-polarized polyester capacitors
1	C3	220uF	Negative voltage filter, polarized electrolytic capacitor (16v) from 100uF it will be fine.
1	C4	10uF	Charge-Pump capacitor, polarized electrolytic capacitor (16v)
1	C8	22uF	$V_{in}$ capacitor, polarized electrolytic capacitor (50v)
3	C5, C6, C7	4.7uF	Voltage dividers load capacitance are required, from 1uF to 10uF, polarized electrolytic capacitors (16v)
6	C9, C10, C11, C12, C13, C14	100nF	Noise filters, non-polarized ceramic capacitors should be close to the device (within 5 mm of the pin)

Quantity	References	Value	Comments
2	D1, D2	1n5819	(400mil) Low drop power Schottky rectifier diode
3	D3, D4, D5	1n4148	(300mil) General purpose small signal high-speed switching diode
1	D6	BAT49	(300mil) Very low turn-on voltage small signal Schottky diode (Vf=180mV)

Quantity	References	Value	Comments
1	Q1	BC557B	TO-92 BJT PNP like as BC557A, BC558, 2N3609 (EBC pinout warning), etc.
1	Q2	IRF530N	TO-220 MOSFET N-Channel like as IRF520, IRF540, IRLZ44N or similar.
2	Q3, Q4	IRFU5305	TO-251 MOSFET P-Channel low $RDS_{on}$
2	Q5, Q6	2N7000	TO-92 MOSFET N-Channel general purpose

Quantity	References	Value	Comments
2	Z1, Z2	TL431	TO-92 Adjustable precision voltage reference ($V_{ref}=2.5v$)
1	U1	AD620	DIP-8 Low cost, high accuracy instrumentation amplifier (INA129 gain equation compatible)
1	U2	CD4066B	DIP-14 Quad bilateral analog switch, CMOS device type “4066” compatible such as HEF4066, HCF4066, 74HC4066, M74HC4066, MC14066, MAX4066, etc. $R_{on} @5v$ must be measured to add to R2.
1	U3	LM393	DIP-8 Dual independent low offset voltage precision comparators
1	U4	ICL7660A	DIP-8 Switched-Capacitor voltage converter (Intersil/Renesas)

Quantity	References	Comments
1	LCD display 16x02 (5v) HD44780 or similar
1	LCD I2C adapter (PCF8574)
1	Active buzzer 5v (12 mm) (7.6mm pitch)
3	Button SPST (normal open) 12mm
4	Header connector 2-Pin JST male (2.54mm pitch)	Optional
1	Header connector 4-Pin JST male (2.54mm pitch)	Optional
1	Terminal block connector 4-Pin (5mm pitch)	Optional
1	Enclosure Bahar BDC30001-A	Optional