Easy Test power battery by BC547

A friends at use the battery often meet a problem electric its energy is finished in important always may many good if there is the circuit warns before or there is the way checks at the beginning. By this circuit Continue reading

Battery 1.5V or 3V Monitor using LM3909

We come to add LED Flasher for Monitor the electric current of battery 1.5V and 3V. By use the integrated circuit LED Flasher or Oscillator. By the rate something flasher equal to 2V. This circuit eats electric a little current Continue reading

Battery Low Voltage Detector using IC 8211

This circuit can use with power supply since 5 volt until 25 Volt. When voltage of power supply or battery agree come to lower location level keeps. It make LED bright show know. Although the circuit this use how many Continue reading

In Circuit Transistor Checker

This simple circuit has helped me out on many occasions. It is able to check transistors, in the circuit, down to 40 ohms across the collector-base or base-emitter junctions. It can also check the output power transistors on amplifier circuits. Continue reading

Digital Step-Km Counter with IC 4026,4024

Max. range: 9,950 meters with two digits Slip it in pants’ pocket for walking and jogging Parts: R1,R3____22K 1/4W Resistor R2________2M2 1/4W Resistor R4________1M 1/4W Resistor R5,R7,R8__4K7 1/4W Resistor R6_______47R 1/4W Resistor R9________1K 1/4W Resistor C1_______47nF 63V Polyester Capacitor C2______100nF Continue reading

Digital Volt and Ampere meter by CA3161E + CA3162E

Voltmeter: Short circuit in the input, pins 10 and 11 [IC1] and we regulate the RV1, until we take clue in the Display, zero in all the digits. We rectify and connect in the input a external voltage roughly 900mV. Continue reading

single digit voltmeter by IC 4028 LM311

First bear it in mind that it is a single digit voltmeter which is 0-9 counts only on the positive side, that is it can measure +0 to +9V DC +/- 1V error. That may not be practical for the Continue reading

Prescaler with Counter by IC digital 4511,74190

Digital frequency counter is being used for wide range of applications. Digital frequency counter extensively uses digital circuits and hence fairly good knowledge of digital circuits and of digital integrated circuits is required to understand the operation of the frequency Continue reading

LED Oscilloscope by LM3914,4017

George Katz of Balgowlah Boys high in Sydney presented a solid state oscilloscope. He says “probably the best advantage is its very small size and the fact that it can run off the power supply of the circuit being tested. Continue reading