The HSR312 and HSR412 devices consist of a AlGaAs
infrared emitting diode optically coupled to a power
MOSFET detector which is driven by a photovoltaic generator.
The devices are housed in a 6-pin dual-in-line
package. The HSR312L and HSR412L employ an active
current limit circuitry enabling the device to withstand
current surge transients.
Posted on Saturday, January 15, 2011 • Category: Miscellaneous
An opto-coupler is a device that can be used to electrically isolate two circuits, so that a voltage spike or other problem on one side will not destroy the circuit on the other side. A common use for them is when you want to interface a computer to an AC-powered device, such as a light or a motor. Usually, the opto-coupler will not be used to control the device directly, and instead will just transfer a signal from one circuit to another.
Posted on Friday, January 14, 2011 • Category: Amplifiers
DS1802 is a Stereo Digital Volume Control IC. It consists of two 65-position, 45kΩ digital potentiometers with logarithmic resistance properties incrementing 1dB per step. It can be operated under automatic software control via a serial 3-wire interface where wiper settings are written with 8-bit words, or under push button control with simple contact closure. The part can be used in either 3V or 5V environments and anywhere within the industrial temperature range of -40°C to +85°C. The DS1802 supports daisy-chaining with other devices under single-processor control.
Posted on Wednesday, January 12, 2011 • Category: Test and Measurement
A pair of AD8307 RSSI (Received Signal Strength Indicator) chips are used to produce DC voltages that are proportional to the logarithm of the Forward and Reflected power levels. These DC voltages can then be subtracted in an Op Amp to produce a voltage proportional to SWR which is essentially independent of power level. The Forward DC voltage also drives a separate Power meter. I have modified Paul's design to use a "Stockton" directional coupler, and to provide a peak-reading capability. The meter automatically provides an accurate readout of SWR for any power level between 10mW and 1000W. I arranged for the Power meter to cover the range 100mW to 1000W, but it is easy to change the circuit to set upper and lower power limits to any values in the range 100uW to 1000W.
Circuit-Zone.com © 2020. All Rights Reserved.