This is the list of components. There may be errors.

You can help stocking by writing your estimated needs to the bottom.

AfreshBoard BOM:

Lambda circuit:
R34.7k1% holeMax pump current 3mA.
R6, R12100k .SMD 1206
R9100k1% hole.
R1320k 1% hole.
R1810k 1% hole.
C12 100n .RM2.5
RHACK4.7kholeSeries resistor between OP and ADC, a trace need to be cut.


T2 TIP121 TO220 Darlington NPN that that meet: 4A, 40W, 40V, hfe>=1k.

xR1 1ohm 1% TO220 Caddock Coolpak MP930 30W TO220 resistor for heater current measurement.

xC4 0.1u 1206 Input filter for heater driver f-3dB 16Hz

R11 100k 5% 1206 Input filter for heater driver

R34 20k 5% 1206 OP feedback

R35 10k 5% 1206 Op feedback

xR4 2.4k 5% 1206 Voltage divider for heater voltage measurement

xR5 4.7k 5% 1206 Voltage divider for heater voltage measurement

Power supply:

IC4 L7805CV (ST) TO220 Most 7805 type regulators will work. Aim for at least 1A. (check LM2940T)

DC1 Traco TMA0515D DC/DC converter +-15v, +-35mA.

C1 1u RM5 0.33 and up

C2 1u RM5 0 to 1u.

C23,24,27,28 1u RM2.5

C29,30,31,32 1u RM2.5

D3 P2KE18A/P2KE20A Taiwan semiconductor. Transient suppression diode, also main component in the wrong polarity protection.

D1 1N4004 Wrong polarity protection. At least 1A rating.

D6 not used Can't figure out why I included it...

IC4 L7805CV (ST) Minmum current rating 1A.

F1 RC5 fuse Short circuit and wrong polarity protection.

R61 200-2k 1206 Serial resistor for power led.

D8 LED RM2.5 Power led


C11, C15,C17,C18. 1u SMD 1206 If MAX232A or MAX202 is used the caps can be 0.1u.

U$2 MAX232 SO16N MAX 232A and MAX202 can also be used.


U$4 LM50 SOT23 Or LM45. 1 Euro.

R21=R24 470k 1%! 1206 Must be matched! Patience will be awarded.

R25=R28 470k 1%! 1206 Must be matched! Patience will be awarded.

R22=R23 4.7k 1%! 1206

R26=R27 4.7k 1%! 1206


xR29,R31 Not used, gain adjustment.

xR30,R32 1k pot hole Type 64, vertical. For offset adjustment

xR10,R33 47k 1206 For offset adjustment.

The offset adjustment can cause problems if the supply voltage are unbalanced, we will probably need to hack the offset adjustment a bit.

LT1882 does not need offset adjustment.


All OP's are LT1882. LM124/224/324 may work. I use 324 initially. (Jörgen) 7 Euro

Atmel ATMega 128-16AI (16MHz, TQFP64) 18 Euro

Microchip MCP3208CISL(external 8ch 12bit ADC) 5 Euro

The HIP 9011 are available in many versions, we don't know which one we want yet. 8 Euro


PCB (15 Euro) - not in the set called every_chip

generated list:

Component number hints for groupbuy. This helps stocking:

MG: 3*every_chip, 5*PCB

JK: 3*every_chip, 6*PCB

MP: 1*every_chip + 1*PCB + 2*extra MAX232 + 5*MC34151P(1 Euro) + 1*L293NE(5Euro)?

MK: 1*every_chip + 2*PCB

DB: 1*every_chip + 2*PCB

DS: 1*every_chip + 2*PCB

MH: 2*every_chip + 2*PCB

These have been airmailed. Every_chip meant only atmega, max232 and LM324

soldered on. 40 Euro (or equivalent). The rest has not been ordered yet.

Further orders via mail: cell at

go back to AfreshBoard