FAQ
TL;DR: LCR-T4 auto-tests 14 part types, draws only 12-15 mA per measurement, and “will be useful in every workshop” [Elektroda, TechEkspert, post #16556695] Accuracy stays within ±2 % for most resistors. Firmware flashing adds live-scan mode and Zener tests. Why it matters: you get multimeter-level insight from a €10 gadget.
Quick Facts
• Supply: 9 V battery; 12-15 mA active, 20 nA sleep [Elektroda, 16556695]
• R range: 0.1 Ω – 50 MΩ, C range: 25 pF – 100 000 µF, L range: 0.01 mH – 20 H [Elektroda, 16556695]
• Typical accuracy: ±1 % R, ±3 % C, ±5 % L (user tests) [Elektroda, 16556695]
• ESR read-out for electrolytics ≥1 µF [Elektroda, post #16556695]
• Open-source firmware: AVR-based, 40 V boost for Zener mode [Elektroda, 16666684]
1. Which components does the LCR-T4 recognise?
It auto-detects resistors, capacitors, inductors, diodes (single & dual), LEDs, Zener diodes (≤30 V with updated firmware), BJTs, MOSFETs, JFETs, IGBTs (basic), thyristors, triacs, and voltage regulators [Elektroda, #16556695; #16666684].
2. How accurate are its measurements versus a quality multimeter?
User comparison showed 9.97 kΩ read as 10.18 kΩ (2 % high) and 100 µF read as 99.6 µF (0.4 % low) [Elektroda, 16556695] Inductance errors rise above 5 % near the 0.01 mH limit.
3. How do I calibrate the tester?
- Short pins 1-2-3 with low-resistance wire.
- Hold the single button until “Self-Test” appears.
- At 38 % remove jumper; at 82 % connect a >100 nF capacitor between 1-3 [Elektroda, 16556695]
4. What battery life can I expect?
A 550 mAh alkaline 6F22 supports roughly 30 000 tests (≈15 mA × 2 s each); users reported >2 years on one cell [Elektroda, bestler, post #16671201]
5. Why does my inductor show "resistor"?
The MCU flags coils below 0.01 mH or above 20 H as resistive. Bifilar wound or high-resistance windings can also be misread [Elektroda, 16708279]
6. Triac appears as NPN—faulty?
Not necessarily. High-gate-current triacs (e.g., KT207) may be detected as NPN when pin order flips. Confirm by testing both 180° rotations [Elektroda, 16585086]
7. What gains do I get from flashing new firmware?
Newest Git build adds: live-scan (continuous R/C/L), PWM & frequency generator, Zener/IR-LED test to 30 V, Polish UI, and logo support [Elektroda, 16666684]
8. How do I flash the AVR safely?
Use an ISP programmer, set fuses: LOW 0xE2, HIGH 0xD9, EXT 0xFC. Backup the factory hex first; then write the compiled .hex, verify, and power-cycle. Full guide in forum post #16666684.
9. Can I measure ESR in-circuit?
Yes for electrolytics ≥1 µF. Testers showed identical ESR values before and after desoldering PC-motherboard caps [Elektroda, Dydelmax, post #16669734]
10. What’s an edge-case the tester fails?
Charged capacitors can kill the input; one user cracked the LCD after a 50 V part was connected [Elektroda, 16579821] Always short large caps first.
11. How do I protect the ribbon display?
Stick 1 mm foam tape under the LCD and avoid flexing the gold ribbon. A clear acrylic case with 10 mm standoffs prevents pressure on the button [Elektroda, 16674114]
12. How do I assemble the acrylic enclosure?
Follow this 3-step: 1. Sandwich PCB between 10 mm spacers; 2. Insert LCD through front panel, secure with nuts; 3. Add rear plate and eight M3 screws [Elektroda, 16658664]
13. Why does the tester mis-show varicaps?
It measures junction capacitance at one bias only, so it logs them as ordinary diodes. A manual curve-tracer is needed for full C-V plots [Elektroda, 16689532]
14. Where can I buy or what’s the typical cost?
Ready-made LCR-T4 kits ship from AliExpress or eBay for €8–12; Polish stock adds ~40 % markup [Elektroda, 16567602] Shipping weight fits <2 cm letter rate.
Does he report himself, I did not even look at it carefully. For sure at the start, it shows the battery voltage. If there is interest, I can undress him and take photos of the guts. But this is next week, because he was at work. As for others, especially those DIYs without housing - I do not know. We were looking for a complete "ready", because no one at work would play sculpting, some modding, etc. In the Chinese there is a lot of it, there are also versions for self-assembly (plate and elements separately). As mentioned by one of the foreheads, Aliexpress or similar are now a mine of electronic gadgets-ideas. Example of search results with the keywords "transistor diode tester": https://en.aliexpress.com/wholesale?catId=0&i...0701011119&SearchText=transistor+diode+tester
I have this tester for 2 weeks. It is with housing - measurement of frequency - frequency generator - checking of IR remote controls - temperature and humidity measurement - the rest was mentioned.Cena-65.72PLN-DIY version. I've seen here comparison of indications with the meter for 2500PLN. As for me amateur is great. it takes a couple of hours for me - 4 hours. Free delivery. I recommend it to everyone.
