@grossdan That window alarm thing is a magnet and reed switch.
First computer 1959. Retired from my own computer company 2004.
Hardware - Expert in 1401, and 360, fairly knowledge in PC plus numerous MPU's and MCU's
Major Languages - Machine language, 360 Macro Assembler, Intel Assembler, PL/I and PL1, Pascal, Basic, C plus numerous job control and scripting languages.
Sure you can learn to be a programmer, it will take the same amount of time for me to learn to be a Doctor.
@ronalex4203 thank you, these magnets are beautiful ...
@grossdan Yes, when I worked there if a guy came in and wanted to know if they were very strong we would put one of the 1" magnets on some mild steel and ask him to remove it. Can't be done without sliding the magnet to the edge and even then it takes a lot to get it off. I have got a blood blister when I inadvertently got my finger tip between two of the larger magnets. They can easily induce a current in a small coil placed under the board at each square.
First computer 1959. Retired from my own computer company 2004.
Hardware - Expert in 1401, and 360, fairly knowledge in PC plus numerous MPU's and MCU's
Major Languages - Machine language, 360 Macro Assembler, Intel Assembler, PL/I and PL1, Pascal, Basic, C plus numerous job control and scripting languages.
Sure you can learn to be a programmer, it will take the same amount of time for me to learn to be a Doctor.
@binaryrhyme i see, the "trick" is to either allow the current to go through T3 and thereby "short circuiting" the led, or T3 is off, and then the current goes through the led.
I guess if T3 is switched on, then the resistance is almost non existence or very low in comparison to the led.
@ronalex4203 One of my places to shop! Can browse for hours. 🙂
I edit my posts to fix typos, correct grammar, or improve clarity. On-screen keyboards are evil.
@grossdan Yes sir. There are lots of inverter designs - you can use a PNP transistor's natural inversion as well.
I edit my posts to fix typos, correct grammar, or improve clarity. On-screen keyboards are evil.
@grossdan, Hi..just to add in what @robotBuilder @BinaryRhyme, and others have contributed to your query..A BJT ( Bipolar junction transistors) base is controlled by base current, but also, it has a "potential hill" to overcome, that is, the .6 to .7 volt drop across the base to emitter.. this "hill" is the threshold that has to be overcome to allow current to flow, so effectively, bring the voltage lower then this "potential hill" , and the junction of the transistors base to emitter is reversed biased and will not permit current to flow. This is how they do it in chips by using internal pull down resistors to pull the base down to ground on NPN, to to Vcc on PNP type... There are many good videos on basic transistor theory, design, and application, so you can get the basic concept and theory on how, and why they work...it's been 49 years since I went to electronics class, so some things are a little rusty, but the basics never fail you...lol
Have fun learning and doing..and be safe!
Kind regards,
LouisR
LouisR