Survival Cheat Sheets ===================== Full new section text from Survival Solutions Electronics Cheat Sheet: Circuit & Schematic Symbols ==================================================== https://noinbox.dev/survival/solutions/electronics-schematic-symbols.html Field principle This reference uses simplified educational symbols. Real component standards and regional symbol styles differ; always check the device datasheet and schematic legend before connecting anything. Quick visual reference. Read the explanations and limitations before use. On this page Common passive and source symbols - Resistor — zigzag or rectangle: Limits current or divides voltage. Value is measured in ohms (Ω). - Variable resistor / potentiometer: Arrow across resistor: adjustable resistance or voltage divider. - Capacitor — two plates: Stores electric charge; polarized capacitors have polarity markings and must be oriented correctly. - Inductor — coils: Stores energy in magnetic fields; often used in filters and tuned circuits. - Battery — long/short parallel lines: Provides DC electrical energy; the longer line conventionally indicates positive. - Ground / common: Electrical reference node. Signal ground does not automatically mean safe protective earth. - Fuse: Sacrificial overcurrent protection; value and type matter. Active components and controls - Diode: Conducts primarily one way; line on symbol identifies cathode. - LED: Light-emitting diode with arrows pointing outward; requires suitable current limiting. - NPN / PNP transistors: Three terminals; emitter arrow direction distinguishes type (NPN points out, PNP points in). - Switch, normally open: Closes a circuit when activated; momentary switch returns when released. - Antenna / transformer / speaker: Input/output and coupling symbols vary; check the schematic key. Reading a circuit safely - Start at the power source: Find battery positive, return, ground symbols and expected polarity. - Trace connections: A junction dot indicates connected wires; crossed lines without a dot often do not connect, depending on drawing convention. - Check ratings: Match resistor wattage, LED current, capacitor voltage and supply polarity to the parts. - Use extra-low voltage: Build learning circuits with isolated low-voltage battery sources only; never experiment on mains or rescue transmitter circuits. Quick component checklist Marking | Meaning | Safe first check R | Resistor | Resistance and power rating C | Capacitor | Voltage rating and polarity L | Inductor | Inductance and current D / LED | Diode / LED | Polarity and current limit Q | Transistor | Part number and pinout F | Fuse | Approved type and rating Further reading & source material Use these sources to validate local rules, technical standards and updates. No emergency article replaces official alerts or trained responders. - IEEE — Symbols resources - IEC — Electrotechnical standards - Existing low-voltage circuit guide Related quick references Morse code reference Radio field guide Back to Survival Cheat Sheets SOURCE LINKS https://standards.ieee.org/ https://www.iec.ch/ https://noinbox.dev/survival/solutions/low-voltage-communication-circuits.html ------------------------------------------------------------------------ Map Symbols Cheat Sheet: Terrain, Contours & Legends ==================================================== https://noinbox.dev/survival/solutions/topographic-map-symbols.html Field principle Map colors and symbols are not universal: read the map-specific legend. The examples here are representative topographic-map conventions, not a substitute for the legend printed on your map. Quick visual reference. Read the explanations and limitations before use. On this page Map lines and landforms - Contour line: Connects points of equal elevation; spacing indicates slope steepness. - Index contour: Heavier contour line often labeled with an elevation value. - V-shaped contours: Where contours cross a stream valley, their V typically points upstream; confirm with neighboring terrain. - Ridge and saddle: Ridges are elongated high ground; a saddle is a lower pass between peaks. - Depression contours: Hachures on closed contours can show enclosed lower terrain. Frequently seen features - Blue line or area: Usually watercourses and water bodies on many topographic maps. - Green fill: Often wooded or vegetated areas; specific meaning depends on map. - Brown contours: Elevation lines in many topographic products. - Black or gray lines: Buildings, trails, roads and infrastructure; line style may distinguish route quality. - Dashed tracks: May indicate trails, footpaths or approximate features; verify the map legend. - Grid lines: Coordinate references used to locate and describe a position. Read the legend before travel - Scale example: At 1:25,000, 4 cm on the map represents 1 km on the ground. - Contour interval: A 10 m contour interval means neighboring contours differ in elevation by 10 m. - North references: True, grid and magnetic north may differ. Read the declination diagram and map publication date. - Hazards and access: Symbols do not guarantee a route is passable, permitted or safe today. Further reading & source material Use these sources to validate local rules, technical standards and updates. No emergency article replaces official alerts or trained responders. - USGS — Topographic map symbols - USGS — Declination reference Related quick references Field mapmaking Compass bearings Back to Survival Cheat Sheets SOURCE LINKS https://www.usgs.gov/educational-resources/topographic-map-symbols https://www.usgs.gov/faqs/what-declination ------------------------------------------------------------------------ Morse Code Cheat Sheet: Alphabet, Numbers & SOS =============================================== https://noinbox.dev/survival/solutions/international-morse-code.html Field principle Morse is a pattern of short and long signals, not a language. Practise with a battery LED, whistle or other permitted signal method; transmitting by radio can require authorization. Quick visual reference. Read the explanations and limitations before use. On this page Timing and distress signals - Dot: Basic signal unit (one unit). - Dash: Three dot units. - Inside a letter: One unit of silence between elements. - Between letters: Three units of silence. - Between words: Seven units of silence. - SOS: ... --- ... (repeated as needed). In formal Morse procedure SOS is a continuous prosign without letter gaps. - Check response: Do not assume a coded light or sound signal has been noticed; prioritize official emergency channels. Practical field drill - Prepare: Use a fixed light source or low-voltage battery LED and agree on the alphabet before use. - Begin slowly: Send a familiar short word using clearly distinct signal timings. - Receive: Listen or watch for full letter groups; write down the character only after the letter-space. - Confirm: Repeat essential information and verify that the recipient understood it. International Morse alphabet and numbers Dot = · = short. Dash = − = long. The characters below are International Morse, not an audio recording. A : ·− B : −··· C : −·−· D : −·· E : · F : ··−· G : −−· H : ···· I : ·· J : ·−−− K : −·− L : ·−·· M : −− N : −· O : −−− P : ·−−· Q : −−·− R : ·−· S : ··· T : − U : ··− V : ···− W : ·−− X : −··− Y : −·−− Z : −−·· 0 : −−−−− 1 : ·−−−− 2 : ··−−− 3 : ···−− 4 : ····− 5 : ····· 6 : −···· 7 : −−··· 8 : −−−·· 9 : −−−−· Reference: ITU-R M.1677 international Morse code standard. Further reading & source material Use these sources to validate local rules, technical standards and updates. No emergency article replaces official alerts or trained responders. - ITU-R M.1677 — International Morse code Related quick references Schematic symbols Radio stations and communication Back to Survival Cheat Sheets SOURCE LINKS https://www.itu.int/rec/R-REC-M.1677/en ------------------------------------------------------------------------ Radio Communications Cheat Sheet: Listening Stations & Signals ============================================================== https://noinbox.dev/survival/solutions/radio-listening-stations.html Field principle Listen to authorized public broadcasts and permitted radio services. Monitoring private communications and transmitting without authorization may be illegal. Frequencies and channel allocations depend on country; check the local regulator and official notices. Quick visual reference. Read the explanations and limitations before use. On this page Radio bands and what to expect - Medium wave / AM broadcast: Roughly 0.5–1.7 MHz depending on region; carries public broadcasts. - FM broadcast: Typically 87.5–108 MHz in Europe; public broadcasting and news. - Shortwave HF: Roughly 3–30 MHz encompasses multiple broadcast and licensed radio services; reception varies with solar conditions and time. - VHF marine channel 16: 156.800 MHz: international maritime distress, safety and calling voice channel; not a general entertainment channel. - VHF marine channel 70: 156.525 MHz: digital selective calling (DSC) only, not voice traffic. - NOAA Weather Radio (United States): 162.400–162.550 MHz across seven designated frequencies; regional coverage. - Amateur radio: Permitted frequencies vary by region, class and licence; listen or transmit only as legally authorized. What a listening station is - Official weather/alert broadcasts: Use public radio channels and official local alert sources. NOAA Weather Radio applies in the US, not globally. - Marine coast radio / MRCC: Coast stations and maritime rescue coordination centres provide safety services; coverage and listening schedules vary. - Voluntary vessel radio watch: Marine crews may keep a watch on safety channels under local rules and operational conditions. - Shortwave broadcasts: International broadcasts can travel far; keep a printed local station/frequency and schedule list and test reception. - Radio scanner caution: Do not attempt to intercept private, encrypted or restricted transmissions. The ability to receive a signal does not automatically make interception lawful. Make an emergency call clearly - Choose correct channel: Use the designated emergency channel for your service and country. On marine VHF, Ch 16 is voice distress and Ch 70 DSC alerting. - Lead with urgency: Distress MAYDAY is for grave and imminent danger; follow applicable maritime radio procedures. - State essentials: Who you are; exact location or bearing; nature of emergency; assistance needed; number of people; repeat as instructed. - Conserve battery: Keep nonessential traffic short, listen for responses, and maintain the watch where safe. - Use redundancy: Have alternative ways to summon help such as emergency phone, registered beacon, visual signals and written contact list. Make a quick listening log - Record: Date/time (UTC), station name, frequency, mode (AM/FM/SSB), program, signal strength and source. - Verify: Compare with up-to-date official frequency tables, current station schedules and local band plans. - Do not rely on one source: Coverage changes due to terrain, propagation, outages, regulations and equipment. Further reading & source material Use these sources to validate local rules, technical standards and updates. No emergency article replaces official alerts or trained responders. - US Coast Guard — VHF Channel information - US Coast Guard — DSC distress - Ofcom — radio spectrum and the law Related quick references Morse reference Schematic symbols Back to Survival Cheat Sheets SOURCE LINKS https://www.navcen.uscg.gov/us-vhf-channel-information https://navcen.uscg.gov/dsc-distress https://www.ofcom.org.uk/spectrum/radio-equipment/radio-spectrum-and-the-law ------------------------------------------------------------------------