homemade-circuits

In this article I will explain how to upgrade an EGS002 inverter board to 5kVA power level using the HCPL-3120 or HCPL-J312 opto isolated drivers with isolated inputs and isolated power supply stages. However, the low side MOSFETs are driven through ordinary BJT totem pole configuration such as by using BD139 and BD140 transistor pairs. […]

This circuit is actually a little more advanced LED chaser scanner circuit using two 74LS164 Shift Register ICs together with one NE555 Timer, and yep the light effect looks somewhat similar to those old Knight Rider or Mustang scanner lights which move from sides toward center. The LEDs are arranged in two strips, or sometimes […]

Referring to the following chaser circuit diagram below, we can see a low-frequency, astable oscillator circuit, made up of two gates, IC1a and IC1b, from the IC 4011 quad two-input NAND gate. The operating frequency of this astable is determined by the values of C1 and R11. This circuit configuration works well as a clock-pulse […]

An H-bridge is one very useful circuit arrangement which lets us reverse the polarity across a load, so now with one DC supply we can make current flow through the load in both directions alternately. Because of that, these H-bridge circuits get used in many places like DC to AC inverter circuits, transformer drivers, bidirectional […]

In this post I will explain one useful SCR relay battery overcharge cut off circuit, which also has automatic latching and small trickle charging feature, so now when battery becomes fully charged then charger disconnects automatically, but still a tiny current keeps going into battery slowly. Main Features Main interesting thing here is the SCR […]