The MTX-90 / MTH-90 is a miniature cold-cathode glow thyratron (trigger tube) filled with neon, housed in a glass envelope. Manufactured in the USSR, this subminiature device is a classic component prized by Nixie clock builders and vintage electronics enthusiasts for its ability to act as both a latching indicator and a logic element. The tube is a direct equivalent to the MTH-90 and is often referred to as the MTX90 or MTH90. It is a New Old Stock (NOS) item, never used, and is ideal for restoring vintage equipment or building retro-style, discrete-logic Nixie clocks.

Key Features & Specifications

• Type: Cold-Cathode Glow Thyratron (Trigger Tube)
• Base: Wire-ended, 3 flexible leads
• Heater: None (Cold Cathode)
• Gas Filling: Neon
• Brightness: ≥ 80 cd/m²
• Viewing Angle: ≥ 60°
• Anode Voltage (Free Grid): ≤ 200 V
• Anode Voltage (Grid Tied to Cathode): ≤ 140 V
• Discharge Inception Voltage (Anode-Cathode): ≤ 150 V
• Discharge Inception Voltage (Grid-Cathode): 65–90 V
• Anode Current (Relay Mode, Peak): ≤ 35 mA
• Anode Current (Trigger Mode, Peak): ≤ 4 mA
• Dimensions: 12 mm (diameter) x 42 mm (length)
• Weight: ≤ 4 g

Applications & Compatibility

• Primary Use: Latching single-dot indicator, logic element in ring counters, and relaxation oscillator in vintage-style Nixie clocks.
• Circuit Role: Acts as a trigger tube or ionic relay for low-power signal conversion and sequential logic without transistors or ICs.

Condition

• Status: NOS (New Old Stock). Never used.
• Origin: Made in the USSR.

Why Choose This Tube?

The MTX-90 / MTH-90 is a staple for enthusiasts building discrete, vintage-style Nixie clocks. Its cold-cathode design and latching ability allow it to function as a memory element, enabling the creation of ring counters and logic circuits without modern semiconductors. The tube's neon glow provides a warm, authentic visual indicator, and its subminiature glass envelope with a top-viewing magnifier effect adds a unique aesthetic. As a readily available, ex-Soviet military surplus NOS component, it offers a reliable and cost-effective way to add genuine retro charm to your projects, from restoring old frequency counters to constructing a fully discrete Nixie clock.