Free Simple Circuit Diagram
This is Fluid/Liquid/Water Level Control circuit using LM830. The LM830 can be used to detect absence and presence of aqueous fluids. This application uses two probes and a voltage divider circuit to detect the presence of the fluid. Sometimes, there is a dissolving or plating of the probe is occurred when A DC signal is used. To prevent that problem, […]
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A very long time constant is provided by R1 and C1. C1 discharges and the near zero voltage at its positive lead is applied to the high impedance inputs of the four gates of IC1 wired in parallel when P2 is momentarily closed. The battery voltage is available at Q1 Emitter since the four paralleled gate outputs of the IC […]
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The ADM3251E is a transceiver which has a high speed, 2.5 kV fully isolated, single channel RS-232/V.28. This device is operates from a single 5 V power supply. The device is ideally suited for operation in electrically harsh environments or where RS-232 cables are frequently being plugged and unplugged due to the high ESD protection on the RIN and TOUT […]
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The output of this circuit will be activated when a mix of two tone/frequency is detected on the input. The frequency f is determined by the values of R1 and C1, where f=1/(1.1 * R1 * C1). For security, using dual tone is more secure compared with using only single frequency. With single frequency, someone can easily find the secret […]
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