Wiring Material: electronic

Wednesday, November 12, 2014

Electronic Cricket Match Game

This electronic cricket is a present for Kids. This simple battery powered circuit can be used to play Cricket Match with your friends. Each LED in the circuit indicates various status of the cricket match like Sixer, Run out, Catch etc. The Circuit uses two ICs ,one in the Astable mode and the second in the display driver mode. IC1 is wired as an Astable Multivibrator with the timing elements R1, R2 and C1. With the shown values of these components very fast output pulses are generated from the Astable.

Output from IC1 passes into the input of IC2 which is the popular Johnson Decade counter CD4017. It has 10 outputs. Of these 8 outputs are used. Output 9 ( pin9) is tied to the reset pin 15 to repeat the cycle. When the input pin 14 of IC2 gets low to high pluses, its output turns high one by one. Resistor R3 keeps the input of IC2 low in stand by state to avoid false indications.

Electronic Cricket Circuit Diagram

When the Push Switch S1 is pressed momentarily, the Astable operates and all the LEDs run very fast sequentially. When S1 is released, any one of the LED stands lit which indicates the status of the match. For example, if LED D7 remains lit, it indicates Sixer and if LED 8 remains lit, it indicates Catch out. Label each LED for its status as shown in the diagram. Pressing of S1 simulates Bowling and Running LEDs indicates running of Batsman.

Thursday, September 25, 2014

Electronic Voltmeter Ammeter Circuit Using Single IC 741

Simple Electronic Multimeter High cost deters many hobbyists from buying a conventional multimeter. Since it is difficult to obtain cheap 50 uAor 100uA meters which are essential for a highly sensitive multimeter, an electronic alternative device is suggested to serve the purpose. The circuit shown here gives economic and safe ranges covered to three values : (i) 0-15V, (ii) 0- l5mA, and (iii) 0-150mA.
The ranges can be extended with suitable modifications. The 741 operational amplifier acts as a null detector. its output is equal to the voltage at point A minus the voltage at , point B, multiplied by the device’s very high voltage gain. lf VA is slightly greater than VB, the output is limited by the supply voltage to about 7 volts. lf VA is slightly less than VB, the output is about 2 volts. At the point at which the output changes from low to high or vice-versa, VA is equal to VB to within a very small margin of error. With the switch set to the position shown in circuit diagram (15V range) the potential difference between points A and C is

R3+R4+R5/R1+R2+R3+R4+R5 * input voltage

or 1/30 * input voltage

The forward voltage drop of the diode D3 is about 0.6V and largely independent of battery condition. About 0.5V appears across the variable resistance VRl and a known fraction of this indicated by a scale on the potentiometer appears between points A and C, i.e. it compares the known reference voltage with a known fraction of the input voltage. On the two current ranges, the reference potential difference is compared with the voltages developed across R4 plus R5 on the l5mA range and R5 only in 150mA range. T D2, a light emitting diode, with its current limiting series resistor R9 indicates whether the output of the operational amplifier is high or low. The diode D1 and the condenser Cl provide the facility of measuring alternating voltages and currents. lf the voltage at A momentarily exceeds the voltage at B, then Cl will charge up via Dl maintaining D2»alight until the peak of the next cycle. Without Cl there is no sharp point at which D2 extinguishes for AC measurement. ln use it must be remembered that the indicated readings are all peak values and will thus need to be divided by square-root of 2 to give RMS value for a sinusoidal input. The meter is calibrated directly VRl is scaled 0-15 on the _ 15V range by comparison with a standard meter. This calibration will hold quite closely for current ranges—the agreement depending on the tolerances of Rl to R5. Ten per cent tolerance resistors have been found to be quite successful for these but, if desired, 5 or even 2 per cent resistors provide a worthwhile increase in the accuracy of the current ranges. ln use, the meter is switched to the appropriate range and V connected as for a conventional multimeter. The potentiometer VR] is rotated until D2 is at the point of changing from off to on and then the reading is directly indicated. on the potentiometer scale. The diodes may be any silicon diode. For use of the multimeter in 0- l 50V range, the values of the resistors Rl to R5 may be changed proportionately so that the value of the ratio

R3+R4+R5/R1+R2+R3+R4+R5

is l/300. Then with these values, the multimeter will operate on 0- l 5OV range in the first position (as shown in the existing diagram). The accuracy no doubt will be somewhat ham- pered. VRl has to be calibrated accordingly.

Electronic voltmeter, ammeter circuit using a single IC 741

Thursday, August 21, 2014

Electronic Components As Light Sensor

Electronic components are included in the category of light sensors is LDR, Photo Transistor, Photo Diode, Infrared Receiver. The function of the electronic component is to detect the intensity of light received by the component. The light sensor is often used in electronic equipment such as on television, light a light switch, light intensity measuring instrument.

Electronic Components As Light Sensor

Tuesday, August 12, 2014

Best Electronic Crowbar Wiring diagram Schematic for AC or DC lines

This is Best Electronic Crowbar Circuit Diagram for AC or DC lines. For positive protection of electrical or electronic equipment, use this against excessive supply voltage. Due to improper switching, wiring, short diagram, or failure of regulators, an electronic crowbar schema can quickly place a short schema across the power lines, thereby dropping the voltage across the protected device to near zero and blowing a fuse.

The triac and SBS are both bilateral devices, the schema is equally useful on ac or dc supply lines. With the values shown for Rl, R2, and R3, the crowbar operating point can be adjusted over the range of 60 to 120 volts dc or 42 to 84 volts ac. The resistor values can be changed to cover a different range of supply voltages. The voltage rating of the triac must be greater than the highest operating point as set by R2, II is a low power incandescent lamp with a voltage rating equal to the supply voltage.

Best Electronic Crowbar Circuit Diagram for AC or DC lines

It may be used to check the set point and operation of the unit by opening the test switch and adjusting the input or set point to fire the SBS. An alarm unit such as the Mallory Sonalert may be connected across the fuse to provide an audible indication of crowbar action. (This schema may not act on short, infrequent power line transients).