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Heathkit Transistor Tester In/Out of Circuit Excellent Condition - $40 (Avon Lake)
638 Moore Rd near Unit C
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Cash Sale No Holds call or Text for Local Pick-up Only.
Transistor Behavior and Characteristics You Can Learn
DC Beta (Gain): The tester physically demonstrates how a small base current controls a larger collector current. By calibrating the meter, you learn how to measure a transistor’s amplification factor (β).
Leakage Current I/CEO and I/CBO: You learn that transistors aren't perfect switches. The IT-18 teaches you to read minor current leakages, helping you understand how temperature and material degradation affect solid-state components.
Polarity Identification: By switching between NPN and PNP modes to get a proper reading, you learn how current flows differently through electron-dominant (NPN) versus hole-dominant (PNP) semiconductor materials.
Practical In-Circuit Diagnostic Logic
Circuit Loading Effects: Testing a transistor while it is still soldered into a circuit board teaches you about parallel resistance and capacitance. You learn that in-circuit testers must use low voltages (the IT-18 uses a 1.5V battery) so they don't accidentally turn on surrounding diodes or semiconductor junctions, which would fake a bad reading.
Symptom-Based Troubleshooting: It trains your brain to categorize component failures into distinct electronic states: a dead short, an open circuit, or a leaky junction.
Vintage Circuit Design & Maintenance
If you open the unit up to fix or calibrate it, it serves as an excellent, simple classroom for:
Bridge Circuits: The IT-18 relies on a balance network to measure resistance and gain.
Analog Meter Ballistics: You learn how delicate 100µA d'Arsonval meter movements work and how shunt resistors are used to change the meter's measurement ranges.
Key Features/ Specifications
Measurement Capabilities: Measures DC Beta (gain) from 2 to 1,000 across two distinct ranges (2–100 and 20–1,000). It also tests for I/CEO and I/CBO leakage current up to 5 mA.
Testing Methods: Components can be tested out-of-circuit via an integrated front-panel test socket or in-circuit using attached alligator clip leads.
Visual Display: Features a large, clear 4.5-inch 100µA analog meter. The leakage scale is non-linear and expanded at the lower end, allowing you to read currents as small as 5µA.
Power Supply: Entirely portable, operating on a single 1.5V "D" cell battery. Testing utilizes low voltage, ensuring that accidental incorrect hookups won't damage sensitive solid-state components.