Simple Bill circuit

Simple amplifier 2 watt circuit

NTSC-PAL TV signal identifier

Stereo Amplifier 18 watt circuit

Circuit elements

R1 = 82 kΩ
R2 = 33 kΩ
R3 = 680 Ω
C1, C3, C4, C6, C7 = 100 nF
C2 = 1 nF
C5 = 47 µF
C8 = 100 µF
IC1, IC2 = TDA 2003

Audio Mixer Circuit

Circuit elements:
R1, R2, R3 3 1K 1/4W Resistor
R4, R5, R6 3 10K Logarithmic Pot
R7 1 1Meg 1/4W Resistor
R8, R10 2 10K 1/4W Resistor
R9, R11 2 100K Linear Pot
C1, C2, C5, C6 4 0.1uF Ceramic Disc Capacitor
C3, C4 2 22nF Ceramic Disc Capacitor
U1, U2 2 741 Op Amp
J1, J2, J3 3 Input Jacks Of Your Choice
MISC 1 Board, Wire, Knobs, IC Sockets

Video signal splitter

Echo Application Circuit