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contacts to supply power to the relay coil, thus immediately breaking the connection, only to be reconnected very quickly through the normally closed contacts. It happens so rapidly it vibrates, and sounds like a buzzer. This same rapidly pulsing contact applies the rising and falling DC voltage to
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The vibrator's primary contacts alternately make and break current supply to the transformer primary. As it is impossible for the vibrator's contacts to change over instantaneously, the collapsing magnetic field in the core will induce a high voltage in the windings, and will cause sparking at the
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for the noise. To prevent this, the sound-deadening lining inside the can was sometimes made thick enough to support the vibrator's components by friction alone. The components were then connected to the plug pins by flexible wires, to further isolate the vibration from the plug.
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Since vibrators wore out over time, they were usually encased in a steel or aluminum "tin can" enclosure with a multi-pin plug at the bottom (similar to the contact pins on vacuum tubes), so they could be quickly unplugged and replaced without using tools.
215:(a constant buzzing sound) while in operation, which could potentially be heard by passengers in the car while the radio was on. To help contain this sound within the vibrator's enclosure, the inside surface of the can was often lined with a thick
176:, causing the contacts to open and close rapidly. The contacts interrupt the 6 or 12V direct current from the battery to form a stream of pulses which change back and forth from 0 volts to the battery voltage, effectively generating a
200:). The rectified output is then filtered, ultimately producing a DC voltage typically much higher than the battery voltage, with some losses dissipated as heat. This arrangement is essentially an electromechanical inverter circuit.
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vibrator's contacts. This would erode the contacts very quickly, so a snubber capacitor with a high voltage rating (C8 in the diagram) is added across the transformer secondary to damp out the unwanted high-voltage "spikes".
223:. Since vibrators were typically plugged into sockets mounted directly on the radio chassis, the vibration could potentially be mechanically coupled to the chassis, causing it to act as a
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Vibrators often experienced mechanical malfunctions, being constantly in motion, such as the springs losing tension, and the contact points wearing down. As tubes began to be replaced by
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DC supply available in a car or from a farm lighting battery, it was necessary to convert the steady DC supply to a pulsating DC and use a transformer to increase the voltage.
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it will induce an alternating current in the secondary winding, at a pre-determined voltage based on the turn ratio of the windings. This current can then be rectified by a
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based electrical systems, the need to generate such high voltages began to diminish. Mechanical vibrators fell out of production near the end of the 20th century, but
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were manufactured with various voltage ratings. In order to provide the necessary voltage for a radio from the typical 6 or 12
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systems for the generation of AC voltages for such applications. Vacuum tubes require plate voltages ranging from about 45
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operating off low voltage, there was a requirement to generate voltages of about 50 to 250 V DC from a vehicle's
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88:. A vibrator was used to provide pulsating DC which could be converted to a higher voltage with a transformer,
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180:. Unlike a steady direct current, when such a pulsating current is applied to the primary winding of a
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supply such as farms. These vibrator power supplies became popular in the 1940s, replacing more bulky
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contacts mounted at the ends of flexible metal strips. In operation, these strips are vibrated by an
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38:. The one on the right has been stripped of the aluminum cap so the inner components can be seen.
196:, or by an additional set of mechanical contacts (in which case the vibrator acts as a type of
318:(First ed.). Indianapolis, Indiana: P. R. Mallory & Co., Inc. March 1947. p. 9.
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device that takes a DC electrical supply and converts it into pulses that can be fed into a
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electronic vibrators are still manufactured to be backwards compatible with older units.
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Schematic diagram of a typical circuit to convert low voltage DC to high voltage DC
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An electro-mechanical vibrator from the Grass
Instrument Co. Used as part of a
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to 250 volts in electronic devices such as radios. For portable radios,
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the transformer which can step it up to a higher voltage.
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34:-brand vibrators manufactured by James Electronics, with
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The primary use for this type of circuit was to operate
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Fundamental
Principals of Vibrator Power Supply Design
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357:"Radio Vibrators MikeHaganAntiqueAutoRadio.com"
211:Vibrators generate a certain amount of audible
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50:amplifier in polygraph input amplifier.
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282:Bedford, B. D.; Hoft, R. G. (1964).
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361:www.mikehaganantiqueautoradio.com
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284:Principles of Inverter Circuits
168:The vibrator was a device with
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288:John Wiley & Sons, Inc.
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263:Switched-mode power supply
78:switch-mode power supplies
76:Before the development of
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387:Electric power conversion
333:"Vibrator Power Supplies"
21:Vibrator (disambiguation)
80:and the introduction of
16:Electromechanical device
337:www.radioremembered.org
131:and similar equipment,
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392:Electrical components
198:synchronous rectifier
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248:Mechanical rectifier
19:For other uses, see
219:material, such as
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182:transformer
178:square wave
150:solid-state
134:B batteries
113:accumulator
106:vacuum tube
68:solid-state
64:transformer
36:octal bases
381:Categories
366:2016-01-24
342:2016-01-24
269:References
258:Reed relay
146:transistor
30:A pair of
90:rectified
232:See also
56:vibrator
32:Heathkit
243:Chopper
86:battery
48:chopper
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170:switch
96:using
58:is an
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213:noise
125:volts
94:relay
291:ISBN
188:, a
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156:Use
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