Connect the lamp to the gate of the thyristor, discharge the cap through the thyristor. That solves the turn off problem, especially as the thyristor hold current is much higher then that of a lamp.
Vladimir Vassilevsky DSP and Mixed Signal Design Consultant
555.
Cheers! Rich
On Oct 26, 4:02 pm, Cem Uzunoglu
Sure it is - and nice to study too.
Of course they are, with cap C1 they set the VCO response Hz/V.
AOP #1 is an amplifier w/ gain +1 or -1 (R1=R2) depending of the conduction of Q1. AOP #2 is an integrator w/ time constant R3*C1. AOP #3 is a trigger with treshold R8/R7.
Not the simplest, but quite fine for audio.
You're just baiting Bill Sloman, aren't you, Rich? :-)
Like this...
Add OpAmps to the current mirror turn-arounds to improve headroom and get more tuning range.
Square-wave? Run twice as fast, then divide-by-2 with a D-Flop. ...Jim Thompson
--
| James E.Thompson, CTO | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |
I can see November from my house :-)
Well, believe it or not I do. My phone's ringtone is a 10khz pulsed sine wave. In fact I just checked with a frequency generator patch on my PC, I was still hearing about 16khz, then it fell down quite fast after that. It can be that my hearing curve comes to and abrupt end there, or the nyquist effect from my 44.1khz sampling rate sound card kills it.
But I admit many people don't hear >8khz and it is musically m00t. So let's say 8khz.
It depends on age. When I was young I could hear the 15.625kHz whine from TV sets (line frequency). It stopped irriatating me sometime in my twenties.
-- Bill Sloman, Nijmegen
Well, he did say, "simple." ;-)
Cheers! Rich
But did that apply to the VCO, the 555, or Slowman.
Ken S. Tucker:
I hope so. :D
-- Saluti
I have a _severe_ drop-off above 2kHz... mostly affecting movie and TV watching right now. Ordinary conversation I don't seem to have much trouble. ...Jim Thompson
--
| James E.Thompson, CTO | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |
I can see November from my house :-)
-- Why? Do you want to die?
Cem Uzunoglu:
I believe what you say, I just don't believe that what you're hearing is 10 kHz, unless, by "hearing", you mean "feeling a weird, rather unpleasant noise".
In my first job I drew the PCB for a graphic terminal, but my most appreciated ability was to spot immediately if the newly programmed synch generator was working within the CRT's specs.
Let's say 4186 Hz.
-- Saluti
-- I'm still running at about 16kHz on the high end, but I sometimes have trouble deciphering meaning from the Golden Girls' schtick. What would you attribute that to ?
Recall the chart I posted. Observe the sounds noted by a letter mark at various SPL. That's where all the intelligibility is. ...Jim Thompson
--
| James E.Thompson, CTO | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |
I can see November from my house :-)
John Fields:
Not in the next five years.
You aren't fluent in 'Old lady'? ;-)
-- Politicians should only get paid if the budget is balanced, and there is enough left over to pay them.
4186 Hz it is then. I can't say no to you after all that :)
Cem Uzunoglu:
:)
Yes. That was the idea. A basic 8 bit ladder DAC connected to a microcontroller. But as I understood the complexities like thermal effects and tuning the oscillator to get even an octave of tuned sounds out of 8 bits, This seems to be getting very complex for such a simple project.
There are some digitally controlled oscillators, but they are just too simple to control. They don't pose any challenge, and what is a hobby without a challenge? I think I'll implement the oscillator and do the mixing in the microcontroller.
You know guys, this always happens. Whenever I want to do something the analog way, it always turns out to be too complex for a hobby project. I guess I now understand why even the simplest machines by todays standards were really expensive back in the day.
I never used a UJT, but 555 was my first IC, I programmed PICs and I run Linux. :) I guess the art of analog circuits is kind of lost on my generation.
Cheers! Cem
ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.