T&L Publications

Thanks for your responses, gentlemen.<p>RonH, your linked circuit is exactly what I built before and somehow had 4mA consumption; I will try to build it with THAT brand Op-amp (or comparator)<p>1206DX, could not see the specific application on your helpful link.<p>Built an astable 7555 circuit, inst...

Hello.
The simplest way is to install a 9V battery in SERIES with ONE of the two wires between the telephones, and run buzzers with pushbuttons on a separate circuit, using the SECOND pair of a telephone 4 conductor cord... or bang on the glass to call the other side...
Miguel

Hi fellows.<p>Cannot come up with a solution to make an ICM7555 (or MC1455) timer chip working as stable multivibrator to vary its duty cycle from about 5% to 95% - I cannot use a plain 555 -<p>It is easy to do it with an op-amp instead, but am restricted to very low current consumption (<0.3mA as t...

Hi Daniel.
If you do not get a better response, just apply the brakes whenever you see a telephone company truck parked by a sidewalk telco panel. The guy should know, and maybe has some spare connectors under his truck carpet.
Miguel

Hi.
The vertical deflection output stage is kaput.
Miguel

Hi.<p>Tried, by handwriting lines of soldering paste on shiny finish fiberglas board, the worse case.
An unconnected "string of pearls" is the result as predicted by Stephen.<p>Well, to something else now.<p>Miguel

Hi fellows.<p>The soldering paste used for surface mount components is a mix of solder in microspheres with a binding flux to form a paste. If such paste could be deposited by some modified printer or plotter on bare fiberglass boards (with no copper clad), and then fed to an infrared or not "p...

Hi Grant.<p>Try this:<p>LWR10 Wirewound
Precision Linear Motion Potentiometer
at:<p>http://www.etisystems.com/<p>At your resistance needs; they may sell a sample. Its actuator is a shaft on one end instead of the knob at top, but... not enough choices...<p>Miguel

Hi Grant.
Alternatives ?... hmmmm What about using a 100/500 ohm digital potentiometer IC driven by a whatever value 105 mm fader you have ?<p>Miguel<p>[ April 06, 2003: Message edited by: Externet ]</p>

Hi John<p>My boss invented those in the pure analog sixties, we do not build it any more, but try our site to examine the 642B schematic:<p>ftp://ftp.orban.com/<p>Now they are all DSP driven.<p>Miguel

Hi.
What about power output transistors used in VHF/UHF transmitters ? Motorola makes some.<p>Miguel

Hi Grant.<p>105cm "fader" potentiometers do not exist. If you are doing a search on those figures you will not find any.
Try 105 mm instead.
I have a zillion 105mm linear at 10K if you can somehow live with that value.<p>(105cm is over 40 inches)<p>Miguel

Hi. There are no 12V leds unless they have a built-in circuit to limit current.<p>Leds fed with 12V must have a resistor to limit the current. If the current is limited to 20 mA with a 12V source, the brilliance will be high.<p>If you feed the same led with 3V instead, you can limit the current to a...

Well, do not believe everything you read at the café...<p>I do take my hat off on this :<p> http://www.tinaja.com/glib/casagpat.pdf <p>My patent lawyer in profession for 30 years became REALLY, REALLY hurt to the extent of ripping apart the above document after I showed it to him. He had never seen ...

Hi Scott.<p>Chances are your device in need of 9VAC is meant to be powered by a domestic juice wall adapter; and it has rectification and regulation internally to get somewhere around 5V for the circuitry operation. I would open it, make a diagram of the power input stage, study it, and probably you...