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Showing posts with the label 2 transistor switch

simple on-off circuit

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with this simple circuit you can turn on-off a relay with 2 tactile buttons.

electronic on off switch with only 2 transistors

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the above circuit is a simple but very usefull electronic switch that allows you with a press of a tactile button to switch on or off a load.output current that the circuit can handle depends from the mosfet q2 you use. the circuit is ideal for small projects like a diy led flashlight that you dont want to use a mechanical switch and make it look more professional..i used it to make many flashlights and i designed a small pcb with smd components to fit around the tactile button so you can mount it directly to your project. transistor q1 is not critical and you can use any generic pnp transistor you have laying around. combined with a relay at the output you can make it to switch on-off the output of a bench power supply or an electronic load(i will publish both in the near future).in my tests it can operate from 3.5-25 volts again depending the q2 you are using. pcb and photos coming soon..... q1 can be replaced with:2N3906 - BC557 - BC857 and many more... q2 may be r