Photo Optical Modulator: Photo Optical Modulator - The principle of an optical dc chopper is illustrated in Fig. 14.42. Devices of this type have been used widely in infrared signal detectors, whose output is a…
Solid State Modulator/Demodulator Circuit: A solid state modulator/demodulator circuit is shown in Fig. 14.41. The transÂformer T is driven by an ac source and couples each secondary connected to the two transistor pairs, Q1 -…
Synchronous Vibrator and Synchronous Chopper: Low dc current may be transformed into a high voltage dc by simple chopper action. Although an inductive type transformation process is required, the outÂput dc may be obtained without…
Varactor Diode Symbol: A specially processed junction diode that assumes the properties of a variable capacitor (about 5 - 250 pf) when its dc reverse voltage is varied is called a Varactor Diode shown in…
Transistor Chopper Circuit: Transistor Chopper Circuit - A single transistor used as a dynamic switch to convert low level dc signal to an ac waveform is shown in Fig. 14.34. If the voltage applied to…
Diode Bridge Type Modulator with Transformer Coupling: Diode Bridge Type Modulator - Figure 14.33 shows a silicon diode ring modulator with an associated ac coupled dc amplifier. The amplifier itself has a gain of 65…
Magnetic Modulator: The most reliable substitutes for electromechanical choppers are magnetic modulators. These devices reach a null stability as low as 10 μV, but their response time is often less than 2 Hz and the…
Self Oscillating Converter (Transistorized Chopper Circuit): Self Oscillating Converter (Transistorized Chopper Circuit) - A Transistorized dc to ac converter suitable for low level dc signal is illustrated in Fig. 14.30. The unique property of this…
What is Electromechanical Chopper?: Electromechanical Chopper - An ac amplifier must see ac in order to perform useful work. A fair number of chopping and modulation techniques are available to change direct current, or to…
Chopper Type DC Amplifier: A simple ac amplifier Transformer may be used to amplify a dc input through the use of additional circuit component known as chopper. In this circuit, the dc signal is first…
