Speed 400 Speed Control
Bill Of Material
Reference
Designator(s) or
Quantity Description Digi-Key Part Number R8 560 ohm, 1/8 W 5% resistor 560EBK-ND R4 2.7K 1/8 W 5% resistor 2.7KEBK-ND R3 3.3K 1/8W 5% resistor 3.3KEBK-ND R1, R5, R6 4.7K 1/8W 5% resistor 4.7KEBK-ND R2, R7 33K 1/8W 5% resistor 33KEBK-ND C4 0.0033uF Ceramic Capacitor 1101PHCT-ND C1 (1/2A BEC) 0.1uF Ceramic Capacitor 1210PHCT-ND C1 (1A BEC) 1uF 35V Tantalum Capacitor P2059-ND C3 0.1uF Ceramic Capacitor 1210PHCT-ND C2 56uF 16V Electrolytic Capacitor (low ESR) P5664-ND Q1 2N3906 PNP small-signal transistor 2N3906-ND Q2 2N7000 N-channel small-signal FET 2N7000-ND Q3 IRF9Z34N P channel power FET, TO-220 IRF9Z34N-ND Q4 IRL2203 N channel power FET, TO-220 IRL2203N-ND D1 Red-green LED, T-1 case, 2 leads LT1058-ND U1 (1/2 A BEC) LM2937T-5.0 5v positive regulator, low
dropout LM2937ET-5.0-ND U1 (1A BEC) LM2940T-5.0 5v positive regulator, low
dropout LM2940CT-5.0-ND U2 PIC12C509N processor, one-time
programmable PIC12C509-04/P-ND 1 ea. (option 1) #4 aluminum spacer, 3/16 long J166-ND 1 ea. (option 1) 4-40 screw about 3/8" n/a 2 ea. (option 1) #4 washer n/a 1 ea. (option 1) 4-40 nut n/a 1 ea. Printed circuit, per artwork, single sided 2
ounce copper, FR4 fiberglass or better PC10-ND for a 4x6 board. This easily
has room for 6 boards. 1 ea. Servo plug and attached wire to match
receiver n/a 1 ea. (option 2) 1 SPST on-off switch with attached wires. n/a C5 (option 3) 220 pF, 50V Ceramic SMD capacitor n/a |
Parts are shown for either a 1/2A peak BEC or 1A peak BEC. The 1/2A version should work with any receiver and servo combination so long as the peak load isn't much over 1/2A. The 1A version works with a Hitec 555 receiver, and probably works with all others; however, I have no way of verifying this. If you need 1A, use this version.
Option 1 fastens the two power FETs together with a screw through their tabs and a 3/16 aluminum spacer to spread the heat load between the two FETs, since they do not both generate significant heat at the same time.
Option 2 uses a switch in place of W2 to provide a low-power on-off switch for the speed controller.
Option 3 adds a surface mount capacitor on the servo pulse input. Unless you have seen a surface mount part, you cannot believe how small it is. The minimum order is 100 pieces for $7.00 (but see my offer below.)
The electronic components, exclusive of PC board, spacer, hardware, servo connector and optional switch is $10.40/unit when buying enough for 10 units. I would expect it to cost about $12-$13 for the parts for one unit; however, there is a $5.00 charge for orders under $25.00.
Why DigiKey part numbers? I don't work for DigiKey, nor do I get a commission. However, I have found them to be reliable, they keep things in stock, and they sell to anyone with a credit card.
Copyright © 1998 by Michael J. Norton.
May be copied as desired and modified as needed so long as this copyright notice is preserved.