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Re: LM308 Question
Dear CMOS,
If you're going to 6V you can use a schmitt trigger based CMOS gate (Such as the 74HC14). Put it between the OP Amp and the transistor (Don't forget to raise the value of the resistor - You don't want to over load the gate).
Regards,
Pazam
Dear Nicholas,
Most machines weight the coins.
Every coin has different weight, so by weighting the coin the machine "knows" what coin was inserted.
Easy does it :wink:
Regards,
Pazam
Dear fjpompeo,
What about a transformer, diode and a simple RC filter ?
You can use a transistor for the switching, as the transformer gives the isolation.
If you want even more isolation you can always connect the circuit to simple optocoupler.
Regards,
Pazam
Re: LM308 Question
Mmmmm....
Have you done any measurements using DVM or oscilloscope ?
More data would be useful.
When the output of the OP amp is high (10V I guess) the base current should be something like 90mA.
When the output of the OP amp is low (2V I guess) the base current should be...
how to use you computer cd-rom in a car
Dear samehham,
You can't.
MP3 playing needs processing your CD drive can not do.
I don't think there are CD drives for PC that can play MP3, since most of them are connected to a PC.
As prices are getting low every day, I don't think anyone will bother...
Re: LM308 Question
Dear CMOS,
It seems you have a current issue.
After adding the diodes, have you lowered the series resistance ?
It should solve what you're describing.
Regards,
Pazam
Re: question about controlling an external circuit by using
The following link should give you a start:
https://www.lirc.org/receivers.html
I've built the PC IR receiver they describe, and I use it with my remote control.
It's easy to build and works for several meters.
One thing you should...
Dear Artem,
TI's MSP430F1101A microcontroller has 1K flash and 128 byte RAM.
It's small, low power, has 14 GPIO and cost about 0.99$ for 1000pcs.
And - It's 16 bit.
Mmmmm....
Hittite have switches, DC to several gigahertz.
The URL is:
https://www.hittite.com/
The HMC226 for example, is a nice one. It's DC to 2GHz, works on 3V and has high input and output power spec.
For a differential signal you can use two switches, as the price of one switch is not...
lm308 power supply
Dear CMOS,
You can add a couple of 1N4007 diodes between the output of the OP AMP and the base resistor.
It should solve your problem.
Good luck,
Pazam
The MSP430 price-performance ratio can be harnessed for big applications too.
I've built a system using multi processing, based on dozens of low cost MSP430 controllers.
Each controller done several tasks, and the sum of all was very powerful and low price.
The system was easy to develop using...
Re: MICROPHONE AMPLIFIER
I would like to add another tip:
Think differential (At least at the first stage).
It's recommended, especially if you use the common electret microphone.
Re: st74a
Dear Joaquim,
The way you describe the component and the marking upon it imply that it is Philips BST74A transistor.
If you have any clue of what the circuit does, see if an N-channel D-MOS transistor fits.
In any case I've attached the data sheet.
Good luck,
Pazam
I also recommend the MSP430.
The price vs. preformance is unbeatable.
The 16 bit controllers do much more per cycle, compared to the 8 bit.
They also consume less program memory, hence enabling bigger software on the same memory size.
The MSP430 family is well designed, and v-e-r-y easy to use.
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