By B. Hague
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As soon as regarded as a probable substitute for copper wires, digital conductive polymers are starting to locate functions in numerous digital units. purposes lower than improvement comprise plastic screens, transistors, photodiodes, plastic gas cells, light-emitting printable plastic inks, and chemical and organic sensors.
Extra resources for Alternating Current Bridge Methods 6th ed
Electrically, the DC breaker is located immediately after diodes which isolate the DC and AC power supplies. 2 Power Switch The main on/off power switch controls both the 120/240 VAC and the DC battery power input. 3 Carrier Switch This switch controls power to the RF amplifiers and supplies a logic high to the voltage regulator board, which enables the supply for the RF driver. In addition, the Carrier Switch controls the operating voltage needed by the switching power regulator. A "Lock Fault" or a low pin 12 (/Carrier Off) on the Remote I/O connector will hold the carrier off.
Illustration 6–8 and accompanying schematic complement this discussion. PA voltage and current come from a metering shunt on the power regulator board. The PAI input is a current proportional to PA current; R405 converts the current to voltage used for metering and control. A voltage divider from the PAV line is used for DC voltage metering. Metering 10 2 High Band RF Power High Expand 2 Compress SWR 20 ALC PA DC Volts Wide Band PA DC Amps -6 SWR Over Lock 100 Input 90 PA DC 80 PA Temp 70 60 PA Temperature Supply DC Volts -12 Modulation Fault Audio Input +6 dB +12 dB Carrier Power 50 Stereo 40 Voltmeter 30 -18 20 Low Input Gain Mono Processing ® RF Output Pilot FM500 FM BROADCAST TRANSMITTER Illustration 4–5 Metering Board U406A, U406B, and U407A, with their respective diodes, are diode linearity correction circuits.
1 above, observe the main channel (L+R) level with a modulation monitor. 20 38 kHz Subcarrier Suppression With no modulation, but in the Stereo mode, the 38 kHz subcarrier, as indicated on an FM modulation monitor, should be down at least 40 dB. 21 Additional Checks In addition to the tests and adjustments mentioned in this section, the following checks ensure a complete performance appraisal of the transmitter: 1. Perform a physical inspection, looking for visible damage and checking that the chassis hardware and circuit boards are secure.
Alternating Current Bridge Methods 6th ed by B. Hague