Shared Projects by Eric

Board to adapt TO252-3 transistors to 0.1" pitch through-hole. I used them to replace transistors in a circa-1990 NAD 5000 CD player (Q101-Q109). The original transistors (Qodd: 2SB1237 PNP / Qeven: 2SD1858 NPN) are obsolete Rohm Semiconductor parts and I couldn’t find good replacements in a through-hole package. Instead, I replaced then with onsemi 2SB1215 PNP and 2SD1815 NPN which are parametrically similar, handle more power and are still active and available.

The centers of the three through-holes in this board are spaced 0.158" from the bottom edge of the board for this Sullins right-angle header. The large TO252-3 pad (collector) is surrounded by thermal vias and both sides of the board are copper floods connected to the collector. Suggest ordering 2oz copper to maximize heat transfer to the board.

This is a simple board to give left stick priority for elevator trim activation in Experimental category light aircraft. Do NOT install in a 14 CFR Part 23 (or predecessor regulation) certificated aircraft.

This PCB fits between the solder cups of D-sub connector J1 and is soldered to the connector’s cups. The assembled module fits inside the connector backshell listed in the bill of materials.

All trim switches must pull this board’s inputs to ground. Both outputs from this board pull to ground. Do not connect the outputs directly to a trim motor; the module is intended to provide “up” and “down” signals to an elevator trim controller such as a TCW Technologies Safety-Trim unit or a relay deck.

Connect +12V, trim switches and trim controller to this module using a female 9-pin D-Sub receptacle and appropriate sockets. If a center trim switch is not installed, do not populate pins 3 and 7 of the mating receptacle (the center trim switch is provisioned to accommodate aircraft like the Kitfox, which is designed to have a single trim rocker switch on the center console; adding stick switches results in three sets of switch contacts).

SCHEMATIC & WIRING DIAGRAM: Download here.

BILL OF MATERIALS (Digi-Key): https://www.digikey.com/en/mylists/list/MWE6AGTBZJ

Description: This board is for the “OVM-14 Mk III” Overvoltage Protection Module designed by Robert L. Nuckolls III, as posted to the AeroElectric-List forum. There have been minor changes made to this version, as detailed in the project documentation (see below).

This board provides overvoltage protection for the charging system in an Experimental category aircraft. It’s a “crowbar” type circuit, which is intended to blow a fuse or circuit breaker in the alternator field supply or to open a relay in the AC feed from a permanent magnet stator.

The nominal trip voltages are 16.0V in normal mode and 13.7V in maintenance test mode (both values subject to 1% resistor tolerance). The design is tested and working; see performance on the last page of the documentation PDF.

This project is intended for use in Experimental category aircraft only. Do NOT install it in a CAR Part 3 or FAR Part 23 certificated aircraft without FAA Field Approval.

BOM: Cost is ~$14 for the components to populate this board. Click for a Digi-Key saved list with those parts.

Download: Click here for a .ZIP archive containing full documentation in PDF format, DipTrace v5.1.0.3 CAD files and RS-274X Gerber files.

Interface board for the DS1603NF ultrasonic liquid sensor. Powers the sensor and provides a 20mA constant current 2Hz flashing output for the cathode of an indicator LED. A pushbutton switch in the 12V supply interrupts power, which reboots the sensor and tests the flasher circuit.

Wiring: From the main bus, connect a fused wire to one side of the switch, and to the anode (+, long leg) of the indicator LED. Connect the other switch terminal to the “12V” pad, connect panel ground to the “GND” pad, and connect the cathode (-, short leg) of the indicator LED to the “LED” pad. An LED current-limiting resistor is not needed.

BILL OF MATERIALS:
C1-C3: Vishay K104K15X7RF5TL2 0.1uF 50V X7R Radial Ceramic Capacitor
C4-C5: TDK Corp. FG14X7R1E475KRT06 4.7uF 25V X7R Radial Ceramic Capacitor
D1: Cree, Inc. C503B-RAN-CA0C0AA2 Clear Red LED, 5mm, 2.1V, 20mA, 22,450mcd
J1: JST S4B-XH-A-1(LF)(SN) 4-Position 2.5mm Right Angle Shrouded Header
Q1: Microchip VP2106N3-G 60V 250mA P-Channel MOSFET, TO-92-3
R1-R3: Stackpole RNMF14FTC47K0 47k-Ohm 1/4W 1% Axial Resistor
S1: Pushbutton Switch, Latching Type (Installer’s Choice)
U1: Texas Instruments SE555P Single Timer/Oscillator IC, 8-DIP
U2: Microchip CL520N3-G 20mA Linear LED Driver IC, TO-92-3

Interface board for the DS1603NF ultrasonic liquid sensor. Powers the sensor and provides a 12V output under normal condition and a grounded output under low fuel alarm condition.

Wiring: From the main bus, connect a fused wire to the “12V” pad, connect panel ground to the “GND” pad, connect a momentary pushbutton switch between the “PTT” pad and ground, and connect the “OUT” pad to an EFIS alarm input.

BILL OF MATERIALS:
C1: Vishay K104K15X7RF5TL2 0.1uF 50V X7R Radial Ceramic Capacitor
C2: TDK Corp. FG14X7R1E475KRT06 4.7uF 25V X7R Radial Ceramic Capacitor
J1: JST S4B-XH-A-1(LF)(SN) 4-Position 2.5mm Right Angle Shrouded Header
Q1: Microchip TN2106N3-G 60V 300mA N-Channel MOSFET, TO-92-3
R1-R2: Stackpole RNMF14FTC4K70 4.7k-Ohm 1/4W 1% Axial Resistor
S1: Pushbutton Switch, Normally Open, Momentary Type (Installer’s Choice)