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The {{Title|General Radio 1212-A Unit Null Detector}} was introduced in {{Catalog N}} and remained available through {{Catalog T}}. | The {{Title|General Radio 1212-A Unit Null Detector}} was introduced in {{Catalog N}} and remained available through {{Catalog T}}. | ||
The Type 1212-A Unit Null Detector a wide band logarithmic amplifier used to indicate a balance during bridge measurements. It uses three stages of amplification that are designed to reduce gain as the signal increases. The output of the last stage is available at the rear panel and | The Type 1212-A Unit Null Detector a wide band logarithmic amplifier used to indicate a balance during bridge measurements. It uses three stages of amplification that are designed to reduce gain as the signal increases. The output of the last stage is available at the rear panel and internal vacuum tube voltmeter displaying relative signal strength. The 1212-A null detector is recommended for use with Type [[716-C]] Capacitance Bridge, Type [[1661-A]] Vacuum Tube Bridge, Type [[916-AL]] R-F Bridge, Type [[716-CS1]] Capacitance Bridge, and the Type [[1606-A]] R-F Bridge at frequencies below 5 MHz. Frequency coverage can be extended to 60 Mc and sensitivity improved by the use of the Type [[1212-P3]] RF Mixer ahead of the null detector. The 1212-A requires an external unit power supply, the Types [[1203-B]] or [[1201-B]] unit power supplies are recommended. There are two accessory filters available, the Type [[1212-P1]] High Pass Filter for hum and noise reduction and the Type [[1212-P2]] One Megahertz Filter for use with [[716-CS1]]. | ||
==Specifications== | ==Specifications== |
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