Yeah, that’s what I said: What’s soakage? Well, you can read more about that at the end of the multipage article here. He also discusses power storage, and most importantly, how not to measure leakage. The result is that the leakage of the wiring and test leads becomes noticeable, where one would never notice these
(Read More…)
The photo is of a 2N256 germanium power transistor made by Electronics Transistors. The “314” date code means that it was made during the 14th week of 1963. So this transistor turned 50 years old sometime during early April. I haven’t tried to hook it up, but it’s just cool to think that if it
(Read More…)
These 2N560 transistors are the only ones I’ve seen with plastic for the standard TO-5 case, which is usually metal. The size and shape is identical, even down to the little tab that sticks out. According to the Motorola Semiconductor Data Book (1969), the specifications are: 2N560 Silicon NPN Pd@25 deg. C (ambient): 500 mW
(Read More…)
The LED flashlights I bought in March from Amazon (but shipped from Hong Kong) arrived recently and I’ve had a chance to use them a bit. I paid $5.49 apiece, with free shipping, but I see that the price (as of June 8) has gone down to $4.30, These have a Cree Q5 emitter, and
(Read More…)
This is an old schematic that I drew in Apr of 2005 using SwitcherCAD III (now LTspice). It is taken from the board I built and put in service for several years as a LED test jig for testing the lifetimes of various white LEDs. Needless to say, most of the white LEDs lasted less
(Read More…)
This Joule Thief uses three SS8050 high current transistors, each having a 333 ohm bias resistor (actually three 1k resistors in parallel). At less than a half volt, it gobbles battery current, 49 mA at 0.42 volts. That is a lot more than the typical JT, which drops to a very low current as the
(Read More…)
When the winding gets tough, double up the number of toroid cores, I say. This JT uses toroid cores that are less than 1/4 inch (6.4mm) outside diameter. The wire has to be fine to get several inches wound on a core. So I wound one core with the wire, and then coupled it to
(Read More…)
I assembled the circuit to see if I could come up with an alarm. Wanna make an Open Garage Door Indicator Alarm The circuit uses two transistors in a circuit that needs only a single timing capacitor and timing resistor to determine the frequency. It’s somewhat similar to the flasher circuits I’ve been working on,
(Read More…)
In 2009 we decommissioned the old PBX system after replacing it with a Cisco VOIP phone system. Most of our campuses just got rid of the equipment lock, stock and barrel, but the whole room full remained at my campus. Over the years, I retrieved a few of the boards, each one about 16 inches
(Read More…)
This is from the 1980s, it’s all red LED segments or dots. I tried to find an angle where the ceiling light would not show, but because it’s a bubble lens, just about any angle had that white reflection. The specifications are available on the ‘net. The box outlined in red is one of the
(Read More…)
