Speaker to Earphone Adapter
With Splitter
By Avery R. Davis
Copyright © 2004 Avery Davis
Overview
This circuit lets you use two stereo earphones or headphones with a radio that has only a single speaker output.
Materials required
3ea. 3.5mm stereo jacks, J1-3
1ea. Phono jack, J4
1 ea. 2W, resistor, R1, 10 Ohms nominal, but any value from 6.8 to 22 Ohms will work.
2 ea. Potentiometer, R2-3, 5000Ohms nominal, but any value from 500 to 5000 Ohms will work.
4 ea. 1/4W, resistor, R4-7, 100 Ohms nominal, but any value from 68 to 220 Ohms will work.
2ea. 5-position terminal strips
One project enclosure with metal lid of suitable size, for example 5"x2.5"x2", RS 270-1803
Hook-up wire (18 to 24AWG).
Tools:
Drill or hole punch
Small saw
Wire cutters
Wire strippers
Needle-nose pliers
Soldering iron, 25W to 50W
Construction procedure and set up:
Refer to the pictures and schematic, below.
First, decide on the mechanical layout of the jacks and terminal strips on inside of the metal lid of the enclosure. Drill the appropriate size holes at the appropriate locations, and mount these components. Install the resistors and capacitor on the terminal strips and add wires to complete the circuitry per the schematic.
Schematic diagram for relay box
