"Never apply more than 1000V DC or 750V AC between any input jack and earth ground. Do not measure voltage while the test leads are plugged into the 10A or ACA jacks."
Perhaps the most enduring feature of the 22-805 is its manual. Today, PDF versions of the
RadioShack 22-805 Go to product viewer dialog for this item. is a 24-range digital multimeter characterized by its
-digit LCD display (4,000 counts) and a built-in RS-232 PC interface. This portable unit is designed for field, shop, and home applications and is capable of measuring AC/DC voltage, current up to 20A, and resistance up to Key Specifications & Features
Measurement Ranges: 24 total ranges, including DC/AC current up to 20A, DC voltage up to 1000V, and AC voltage up to 750V.
Display: 4,000-count digital display with automatic and manual range selection options.
Connectivity: Features a serial RS-232 port for real-time data logging and readings on a computer. Safety Rating: CAT II (600V). Core Button Functions
SELECT: Toggles between sub-functions (e.g., switching between DC and AC within a mode).
RANGE: Toggles between auto and manual ranging. Pressing it enters manual mode; holding it for 2 seconds returns the device to auto-range.
HOLD: Freezes the current reading on the screen for easier recording.
Hz/DUTY/WIDTH: Used to measure frequency, duty cycle, and pulse width.
MAX/MIN: Records and stores the highest and lowest readings during a measurement session. Basic Operation Instructions
Safety First: Ensure you are familiar with testing procedures. For high-voltage testing (above 500V), start with the highest range setting and work down to prevent damage.
Continuity Testing: Set the selector to the diode/continuity symbol ( ) and press SELECT until the buzzer icon ( ) appears on the display. radio shack 24 range digital multimeter 22-805 manual
Voltage Measurements: Plug the red lead into the V terminal and the black lead into COM. Turn the dial to ACV or DCV before connecting to a live circuit.
PC Interface: Use the RS-232 port to connect to a PC. It is supported by open-source software like sigrok for data analysis.
You can find the full digitized text of the manual at the Internet Archive.
The RadioShack 22-805 is a versatile, 24-range digital multimeter (DMM) designed for field, lab, and home use. Known for its durable build and 3¾-digit LCD display, it remains a reliable tool for measuring voltage, current, and resistance with high precision. Key Features and Specifications
The 22-805 model stands out with its ability to display up to 3,999 units (4,000 counts) and its inclusion of a computer interface for advanced data logging.
Display: 3¾-digit LCD with an analog bargraph to show measurement magnitude relative to the full scale.
Computer Interface: RS-232 serial connectivity allows users to log and graph measurements on a PC using original MS-DOS or early Windows software.
Auto-Ranging: Features automatic range selection with a manual-ranging override for specific testing needs.
Data Hold: Temporarily freezes the displayed value for easy reading after disconnecting the probes.
Safety Rating: CAT II rated for up to 600V; the meter is protected by double insulation. Measurement Type Maximum Range DC Voltage AC Voltage DC/AC Current Resistance Operating Instructions
Before using the meter, ensure you are familiar with the Safety Precautions to prevent injury or equipment damage. 1. Measuring Voltage
Plug the black test lead into the COM (Common) jack and the red lead into the V/Ω/mA jack.
Set the function selector to the desired DCV or ACV position. "Never apply more than 1000V DC or 750V
Touch the probes to the circuit in parallel. The meter will automatically select the best range for the reading.
Read the value on the LCD display; the analog bargraph will indicate the level of voltage relative to the range. 2. Measuring Resistance
Important: Turn off all power to the circuit and discharge any capacitors before testing. Set the selector dial to the Ω (Ohm) position.
Touch the probes to the component. If the component is part of a circuit, it should be isolated for an accurate reading.
Summary
Build & Design
Measurement & Performance
Battery & Power
Usability
Pros
Cons
Who it’s for
Quick verdict
Suggested alternatives (if you want better accuracy/safety)
Related search suggestions I can provide search-term suggestions to help find manuals, user reviews, or replacement parts.
Here’s a sample blog post or informational article you could use. It’s written to be helpful for someone searching for that specific manual.
Aesthetically, the 22-805 is a time capsule. It sported the classic RadioShack dark grey or black housing, often with yellow or red accent buttons that screamed "1990s utility."
The manual highlighted features that were innovative for the consumer market at the time:
According to the original factory manual, the 22-805 should be calibrated every year if used professionally, or every 3-5 years for hobby use. Without calibration, DC voltage accuracy can drift from ±0.5% to ±2%.
Internal Calibration Pots (from service manual):
Important: Do not attempt calibration without a known reference source. The manual warns that improper calibration voids any remaining safety protection.
Released during the heyday of consumer electronics repair, the 22-805 was marketed as a "24-Range" meter, a term that signaled versatility to the budding electrician. The device was designed to cover the holy trinity of electrical measurement: Voltage, Current, and Resistance.
The manual, often a crumpled pamphlet found in the bottom of a toolbox, outlined a specification sheet that was modest but respectable for its price point:
From top (12 o’clock) counter-clockwise:
You might wonder: is it worth hunting for the 22-805 manual when you can buy a $20 digital multimeter on Amazon?
Reasons to keep the 22-805:
Reasons to upgrade:
If you keep the 22-805, download the manual and store it on your phone. If you buy a new meter, keep the Radio Shack unit as a backup.