Circuit Project Electronic

Special design for shop-windows animation
Useful for many types of touch controls
Parts:
R1,R2_____1M 1/4W Resistors
R3,R4____47K 1/4W Resistors
C1_______10µF 25V Electrolytic Capacitor
C2______470pF 630V Ceramic or Polyester Capacitor
D1-D3____1N4002 100V 1A Diodes
Q1-Q3_____BC337 45V 800mA NPN Transistors
RL1_______Relay with SPDT 2A @ 220V switch
Coil Voltage 12V. Coil resistance 200-300 Ohm
J1________Two ways output socket
Sensor____Aluminium or copper thin sheet with the [...]

Double-tone Police sound
Single-tone old ambulance sound
This circuit is intended for children fun, and can be installed on bicycles, battery powered cars and motorcycles, but also on models and various games and toys. With SW1 positioned as shown in the circuit diagram, the typical dual-tone sound of Police or Fire-brigade cars is generated, by the oscillation [...]

Circuit : Miroslav Adzic - Serbia & Montenegro
Description:
A novel supply voltage monitor which uses a LED to show the status of a power supply.
Click to view circuit and read more
Source :: http://www.zen22142.zen.co.uk/Circuits/Power/svind.htm