Resistance Measurement Analog LED Meter
This is a LED Analog Meter, This can be used as a Resistance Meter and Low Impedance Voltmeter for Battery Levels. To measure battery voltage, […]
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LM555 Voltage Doubler
This circuit shows the voltage doubler working with a 555. LM555 has good drive 200mA, both Vcc and Gnd. 555 has the advantage of having […]
FET Current Source and MOSFET
This is a constant current source using a FET. This is the most simple replacement to series resistor to limit current. The N-Channel FET BF256C […]
BCD Thumbwheel to Voltage Interface
This is a Proportional Controller where the setpoint is derived from a Thumbwheel switch. The conversion of Thumb-wheel Digital Data to Analog mV is similar […]
Battery Backup for SRAM or Microcontroller
This circuit can be used as a low cost SRAM and Microcontroller or Microprocessor Battery Backup. All the diodes are 1N4148, The diodes prevent battery […]
Audio Visual User Interface with Ack
This circuit is an User Interface part of a Security Alertness Monitor that i designed decades ago. The circuits are here – Digital Circuits – Part 1 The RAM […]
Voltage Attenuator Amp – DMM Project
LF356 opamp FET input is in a inverting amplifier configuration here. R4 + R5 make up Ri each 1/4 W MFR withstands 250V so both […]
Thermocouple and Current Input Module
This input module converts J, K Thermocouple and 4-20 mA Inputs to 0-2V Full Scale. These can be used for any voltage/current inputs too. The […]