Wednesday, March 28, 2018

after getting enough of the shortcomings with the quadrature and the wien bridge

these ones are not much better . . . yet :

  • + the oscillation amplitude is determined
  • + the oscillation voltage range is defined (offsets)
  • – unfortunately avail. starting from above the 200Hz
  • + the fixed frequency can be set by RC


a couple of more 5V 32k osc.-s

a tuned (this time) j-Fet amplifier stage


Wednesday, March 21, 2018

yet another 32768Hz Quartz Osc.

Blind tuned to work with some consequences from . . . at 5V v. of it . . .

-- with the single BJT stages and the battery feed and "sensitive"(tuned) oscillators -- it is most unlikely to get anything "properly" to work -- . . . -- moreover with the 1.2 volt battery the grid has to be tuned to work in 3 different areas of operation of the bipolar transistor -- low-voltage (below normal) , normal voltage (for BE CE voltage drops) and hi-voltage (above normal) -- that has to be achieved with fixed biasing elements -- . . . -- in below circuit the critical elements appeared to be C1 , C8 , C4 , C10 -- less C1 more C8 ... also the series connection of C4 and C10 = Cp of the X-tal resonator it first started to "charge" the X-tal with ratio 1.2x : 6x Cp but as i increased C8 the opt. ratio changed to 1.5x : 3x Cp ???

the "above normal" range ↓↓ -- i just fast tuned it just to "charge" the X-tal -- this to see if the current waveform for X-tal goes "trapezoidal" (← failure in a sense of frequency stability -- i assume) or stays Sine . . . . . . . . . well it stayed sine -- but for this one the further frequency tuning and likely some attenuation is a must ↓↓↓↓ (see next) . . .

there is a very simple circuit for 8MHz crystal but (it requires less energy for startup) and it also works only with very narrow range of the supply parameters -- so -- it can't be simply adapted for 32k
. . . ?amazingly i've already proven it otherwise ???

8MHz ::

the C14 caused pulsation is likely causing and the instability in the 5v experiment above ↑↑↑↑

32kHz ::

Low NRG 32k ::

Ultra-tuned UHF ::

nearest match from web

The failed but extremely fast starting UHF resonator Osc. experiment


Tuesday, March 20, 2018

Synchronours Double Quadrature Osc.

Notice the difference in the bottom inverters' biasing

v.2 :: Lo-Frequency


Monday, March 19, 2018

testing out the custom xx78L05xxx variant

amazingly -- worked from scratch -- no matter the blind guessed j-Fet and Zener values and much randomly chosen 2N2222 and 2N2907 for "tech."

but the OUTP voltage little drifts with INP voltage and the fold-back (from140mA) starts to work from 14V external supply ( ? wrong zeners . . . )

the model is currently adjusted to 5.0V at Abs.Max 35.0V input

as usual the component level model (78L05) is more stable than the .cir net-list model ( LT1761-5 )

NB! Not all the plotted parameters are relevant/consistent with the ↑↑ shown test
(they are relics from another grid that was used as a draft for these ones)

"Level 2" ::

. . . with custom LM324 CLM ( Component Level Model ) (( which i also needed to test ))

This is why the net-list models are not good at complex circuits ↓↓ (i actually didn't expect to get it "stable" . . .)


Sunday, March 18, 2018

web buck-boost to custom (Spice-)experimental boost


PS!!! -- Not proofed for startup or for a specific situation switching errors such as (switching fades or changes to too long cycle length = too high current through MOSFET . . .)

-- also it likely can be converted for better efficiency (87% - - might include and some conceptual changes next to just adjusting the inductor and frequency values)

-- target parameters INP : 5V (up to Lim.) 1.5A ; OUTP : about 12V (up to) 200+some mA



Sunday, March 4, 2018

"LM301" test 2

Offset test ::
(was even "passed" to my surprise ? ** is a good Op Amp after all)

However since it's frequency capabilities set it more to audio range - a random internet bootstrapped Op Amp circuit test ::
((this is actually a good - better than expected - result . . . again! **))