Blue Ring Tester Schematic Diagram Exclusive -
The Blue Ring Tester operates on the principle of or "ringing."
After analyzing this , we compared it against a commercial $500 LCR meter. The results were surprising:
tank capacitor, and the LM393 input pins as short as physically possible.
| Component | Value | Purpose | |-----------|-------|---------| | R1 | 10k | Base bias for Q1 | | R2 | 1k | Emitter current limit | | R4 | 10k | Signal output resistor | | R5 | 100k | Attenuation/filter resistor | | C2 | 100nF | Supply decoupling | | C3 | 1nF | High-pass filter | | C4 | 100pF | Low-pass filter (noise reduction) | | Q1 | 2N3904 | NPN switching transistor | | Lx | Unknown | Coil under test | blue ring tester schematic diagram exclusive
A momentary negative-going excitation pulse (typically generated by an onboard 555 timer circuit or a micro-controller tuned to a low frequency like 10Hz to 50Hz) shocks the tank circuit into oscillation through resistor R5cap R sub 5 2. The Comparator Stage (LM393)
Using the Blue Ring Tester is incredibly straightforward. Connect your test leads across the primary winding of the transformer or inductor under test (ensure the circuit board you are testing is completely powered down and discharged).
+9V DC | | | R1 +--/\/\/--+----+----+ | 10k | | | | | --- C2 | | --- 100nF | | | | | | GND | | | | | +--+--+ | | | | | | |/ Q1 | | +-----| 2N3904 | | | |\ | | | | +---+ | | | | | | | | R2 | | | | 1k | | | | | | | | | +---+ | | | | | | | +---+-----+ | | | | R4 | +--/\/\/--+-----> Output to | | 10k | Comparator/ | | | Microcontroller | | --- C3 | | --- 1nF | | | | | GND | | | | | | R5 | +--/\/\/--+ | 100k | | --- C4 | --- 100pF | | | GND | +-----------> Test Coil (Lx) (connected between this point and GND) The Blue Ring Tester operates on the principle
+9V to +12V DC Input │ [ ] R1 (10k) │ ├───●───────┐ │ │ │ [ ] [ ] [ ] R4 (47k) R2 [ ] [ ] R3 [ ] (10k) │ │(10k) │ LM3914 LED Driver │ │ │ ┌─────────────────┐ Pulse Input ●───┼───────┼───►│ Pin 5 (Signal) │ (From MCU/555) │ │ │ │ │ │ [ ] [ ] === │ Pin 1 -> LED 1 │ [ ] R5 [ ] [ ] C2 │ Pin 10 -> LED 10│ [ ] (1k) │ │ (1nF) └────────┬────────┘ │ │ │ │ │ ●────────┴─●────────● │ │ │ │ │ │ │ │ │ │ ===== C1 ├─┐ │ │ │ [ ] R6 (10nF) │ └─┼────────┘ │ [ ] (22k) │ │ │ │ │ │ LM393│ │ │ ●──────────┴─►(Inv) ├───┘ │ │ (Non) │ │ [─] Test ▲ │ │ [─] Probes └────┘ │ │ │ └──────────────────────────────────────────────┴─── GND Components List IC1: LM393 (Low Power Dual Voltage Comparator) IC2: LM3914 (Dot/Bar Display Driver) Resistors: R1, R2, R3: 10kΩ (Metal Film, 1/4W) R4: 47kΩ (1/4W) R5: 1kΩ (1/4W) R6: 22kΩ (1/4W) Capacitors:
This simplified schematic diagram omits several fine details for clarity, such as precise resistor values (except the critical 100Ω and 1kΩ ones) and some decoupling capacitors. The exact part numbers and resistor values can vary between designs.
After extensive research and development, we are pleased to provide an schematic diagram for a blue ring tester. This diagram is designed to be easy to follow and understand, making it accessible to a wide range of users. The Comparator Stage (LM393) Using the Blue Ring
Would you like a detailed explanation of the using a ring tester instead (low voltage, no blue ring), or the theoretical principles behind detecting shorted turns?
Even a reliable tester can malfunction. Common issues and fixes include:
: The tester injects a fast, low-voltage electrical pulse into the component under test (an inductor or transformer winding).
: The circuit uses an integrated circuit (often a CD4015BE or similar timer/logic IC) to send a fast voltage pulse (under 600mV) into the component under test.
Understanding the Blue Ring Tester: Exclusive Schematic Diagram and Circuit Guide