Zusammenarbeit
KUNST
SCHÖNHEIT & WELLNESS
HANDWERK
KULTUR & GESCHICHTE
UNTERHALTUNG
UMFELD
ESSEN & GETRÄNKE
REVERSE ENGINEERING
WISSENSCHAFTEN
SPORT
TECHNOLOGIE
WEARABLES
1/4 W Resistor Kit: Carbon Film Resistors Rated and Colour-Coded to MIL-PRF-22684 Style RL07
A 1/4 W rating is earned, not printed: the US military resistor specification gives its RL07 style 1/4 W at 70 °C only if the resistors survive its tests. Carbon film resistors in a range of values are checked, overloaded for 5 seconds, run for 1,000 hours at 70 °C on a sample, colour-coded with five bands and sorted into a kit.
Result: an assortment of 1/4 W carbon film resistors, ±5 % or ±2 %, each band-coded with its value.
Source: MIL-PRF-22684F, Resistors, Fixed, Film (Insulated) (US Department of Defense, 2006), style RL07. Not given here: the RL07 body and lead sizes and the allowed change in the life test, which are in the RL07 detail sheet. Unknown: the band paint; only its colours are fixed. Picture: Wikimedia Commons.
Fortgeschritten
6 weeks
Anweisungen
1
1
Check each value
Check each value
Measure the dc resistance of every resistor. It must lie within its tolerance of the nominal value: ±5 % or ±2 %. Work out its rated working voltage from E = √(P × R) with P = 1/4 W, but never above 250 V: for example 50 V for 10 kΩ, 9.1 V for 330 Ω. Ours: a Wheatstone bridge.
Materialien für diesen Schritt:
Kohleschichtwiderstand1 assorted values, as many of each as the kit needsBenötigte Werkzeuge:
Wheatstonesche Messbrücke2
2
Overload for 5 seconds
Overload for 5 seconds
Mount a resistor horizontally in still air, nothing within 3 in. of it except the base 2 in. below. Apply 2.5 times its rated working voltage (but not more than 500 V) for 5 seconds. Measure again 30 to 35 minutes later: the change may not exceed ±(0.5 % + 0.05 Ω), with no arcing, burning or charring.
Benötigte Werkzeuge:
Gleichstromnetzgerät
StoppuhrWheatstonesche Messbrücke3
3
Run the life test on samples
Run the life test on samples
Solder sample resistors from the batch to lightweight terminals with 1 in. of lead, spaced so none warms another, in still air at 70 °C (+15, -5). Measure them first, then apply the rated working voltage 1 1/2 hours on and 1/2 hour off for 1,000 hours, measuring at the end of an off period after 250, 500 and 1,000 hours. A batch whose samples pass carries the 1/4 W rating. Not given here: the allowed change, which the RL07 detail sheet sets. Ours: an oven as the 70 °C chamber.
Benötigte Werkzeuge:
Backofen
ThermometerGleichstromnetzgerät
Lötkolben
LötdrahtWheatstonesche Messbrücke4
4
Paint the colour bands
Paint the colour bands
On a body of any colour but black (tan is preferred), paint five bands: first figure, second figure, multiplier (black 1, brown 10, red 100 ... blue 1,000,000; gold 0.1, silver 0.01), tolerance (gold ±5 %, red ±2 %), and a wider white band, about 1 1/2 times the others, for solderable leads. Figures: black 0, brown 1, red 2, orange 3, yellow 4, green 5, blue 6, violet 7, grey 8, white 9. So 330 Ω ±5 % is orange, orange, brown, gold, white. Unknown: the paint; the colours must be permanent and nonfading.
Materialien für diesen Schritt:
Farbring-Markierungsfarbe1 set of coloursBenötigte Werkzeuge:
Feinspitzige Pinsel5
5
Sort into the kit
Sort into the kit
Sort the rated, coded resistors by value into the compartments of a box, one value to a compartment.
Benötigte Werkzeuge:
Sortierbox für SpielmaterialMaterialien
2- 1 assorted values, as many of each as the kit needsPlatzhalter
- 1 set of coloursPlatzhalter
Benötigte Werkzeuge
9- Platzhalter
- Platzhalter
- Platzhalter
- Platzhalter
- Platzhalter
- 2 vendors sell this, none ship to you yetPlatzhalter
- Platzhalter
- Platzhalter
- Platzhalter
Dieser Bauplan stellt her
Verwandte Blueprints
Diese Blueprints teilen Wissen — Techniken, Materialien oder Prinzipien
CC0 Gemeinfrei
Dieser Blueprint ist unter CC0 veröffentlicht. Sie dürfen dieses Werk für jeden Zweck frei kopieren, ändern, verbreiten und verwenden, ohne um Erlaubnis zu fragen.
Unterstützen Sie den Maker, indem Sie Produkte über seinen Blueprint kaufen, wo er eine Maker-Provision von Anbietern festgelegt, verdient. Oder erstellen Sie eine neue Iteration dieses Blueprints und verbinden Sie ihn in Ihrem eigenen Blueprint, um Einnahmen zu teilen.