Resistance Wheel

Resistance Wheel

Resistor is a very vital electronic component used in most of the circuits. The value of resistor is marked on it in colour coded form. There is a special code to read this value. Resistor: Value reading

In this activity, we will design a handy tool resistance wheel which will eliminate the need to memorize the values of color rings.

Material Used: Card Board, geometry box, color pencils.

  • Draw four circles on a card board of radius 5 cm, 4 cm, 2 cm and 1 cm. Mark there center. Cut these circles. Divide each circle in to 11 parts (10 parts of angle 33 degree, 1 part of 30 degree).

  • Color ten parts of the circle in the following sequence: Black, Brown, Red, Orange, Yellow Green, Blue Violet, Grey and White.

  • Label each circle as per the table given below.
  • The first and second ring is the value ring. The third ring is multiplier and the fourth ring is the tolerance one which is usually gold or silver.
Color I Ring II Ring III Ring
Black 0 0
Brown 1 1 0 Ω
Red 2 2 00 Ω
Orange 3 3 KΩ
Yellow 4 4 0KΩ
Green 5 5 00KΩ
Blue 6 6 MΩ
Violet 7 7 0MΩ
Grey 8 8 00MΩ
White 9 9 GΩ
  • Align all four circles at the centre. Make a hole at the centre of each circle.  Take a splitter nail. Insert the nail through all the circles. Bend the nail at the back.

  • Our resistance wheel is ready.

Disco lights

Disco lights

Disco Deewane!! AH HA!!

By using a simple two transistor circuit, we can make LED’s dance.

Circuit Diagram

This is the circuit for Astable Multivibrator. Due to continuous charging and discharging of Capacitor, the LED turns ON/OFF alternatively and appears to dance. We have designed a special purpose PCB for this circuit. No wiring is needed with such PCB. We just have to place the components at the designated place on component side and solder them properly on the reverse side (solder side).

On the solder side, there are conducting tracks inscribed instead of wire connections. This makes the circuit neat, crisp and less cumbersome.

COMPONENT SIDE

SOLDER SIDE

 

 

 

 

 

 

 

 

 

 

 

 

1. First step is to prepare a CID Chart (Component Identification Data). We need to inspect each component of the kit, check its value and mark the polarity.

2. Mount the resistance as per their value marked on the PCB. Resistance do not have any polarity and can be put in any direction but make sure their value is correct. Bend the component’s lead after mounting so that it does not fall when we turn the PCB for soldering.

3. Mount the transistors as per their value and match the direction of mounting with the PCB. The electrolytic capacitor and LED are also mounted as per polarity. Bend the component’s lead after mounting.

4. Now it is time to insert the jumpers (J1, J2 and J3). A jumper is basically a conducting wire which is used to join two points on PCB to make a connection. Here we have cut tin wire to the size and inserted between the two points.
              

5. Turn to the solder side of the PCB. Turn on your soldering iron. Let it heat sufficiently. Straighten the lead of component which you want to solder. Solder all the leads. Cut the extra lead after soldering.


                    

6. Now mount the LED on their place. Insert the longer leg of the LED at the marking “+” on PCB.

7. Solder the LED after mounting.


8. Now solder the snap at required points.

Power the circuit, and let the LED’s dance. ENJOY!!!