Free circuit schematics - wiparat.com

Notes:
* Can be directly connected to CD players, tuners and tape recorders.
* Tested with several headphone models of different impedance: 32, 100, 245, 300, 600 & 2000 Ohm.
* Schematic shows left channel only.
* B1, SW1, J1 & C3 are common to both channels.
* R3 value was calculated for headphone impedance up to 300 Ohm. Using [...]

Pushbutton activated
Very simple circuitry
Parts:
R1______________4K7 1/4W Resistor
R2,R3___________1K 1/4W Resistors
C1____________100µF 25V Electrolytic Capacitor (See Notes)
D1___________1N4002 100V 1A Diode
Q1____________BC547 45V 100mA NPN Transistor
Q2____________BC327 45V 800mA PNP Transistor
P1_____________SPST Pushbutton
RL1___________Relay with SPDT 10A min. switch
Coil Voltage 12V. Coil resistance 150-600 Ohms.
Source : Headlights Timer by BC547, BC327