0-99 seconds/minute 2 Digit Timer

I make this micro controller based timer as a part of shooter training Project.we can select and set time for a period of 0 t0 99 seconds or minutes. when the the timer is start.the 2 seven segment display start counting down .when it reach 0 an out put voltage activate buzzer or relay .so any electrical device can be switched on or off after a time delay

¶Microcontroller based design for greater accuracy and control
¶Power supply input 12 VDC 200 mA
¶Two 7 segments Display to display time
¶Single key start and dual key alarm time set function
¶Power and Relay-On LED indicator
¶Terminal connector for connecting power supply input and relay output to the PCB
¶Onboard regulator for regulated supply
¶Crystal resonator based design for better accuracy

there three buttons Up Down and set button

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Ring tester

In my Electronic repair job I found normal multimeter is somewhat limited in certain area. so special tools are needed for saving a lot of time Ring tester is one of this kind .helping me to check small hi Q inductors SMPS transformer, TV Deflection coils ,LOT ,line driver transformer and almost any inductor working on hi frequency.Normal multimeter can only identify a open coil ,but not a shorted windings. I found some commercial available ring tester. but it is not available in local shops of my area.also it seems priced high. So I decided to make a ring tester of my own. Below is the one I successfully made from the junk box components. I found it very useful. and now it is one of my best test tool collection. Two Ic's, few LED's ,one plastic container and few resistors made this wonderful tool. If we test it with primary of SMPS transformer or LOT windings of a good one shows all its LEDs will light. depending on the inductive reactantce...

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